i

Proceedings

Of

State Level Seminar on

Innovative Trends

in Physics

(ITP – 2016)

10th March 2016

Editors Mr. S. Arumugam, M.Sc., M.Phil.,

Mr. G. Lakshiminarayanan, M.Sc., M.Phil., Mr. S. Vasudevan, M.Sc., M.Phil., Mr. D. Gopinath, M.Sc., M.Phil.,

Organised by

PG & Research Department of Physics Shanmuga Industries Arts and Science College (Co-Ed)

(An ISO 9001-2008 certified institution), Certified Under Section 2(f) of the UGC Act 1956 Affiliated to Thiruvalluvar University, Vellore Manalurpet Road, Tiruvannamalai-606 603.

Phone : 04175-236654 / 237885 / 238744, Fax : 04175-237837 Email : shanmugacollege@gmail.com, Web : www.shanmugacollege.org

Facebook : www.facebook.com / shanmugacollege

ii

All rights reserved. No part of this publication may be produced or transmitted in any form or by

any means, electronic or mechanical, including photocopying, recording,

or any information storage or retrieval system, without prior

permission in writing from the publishers.

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action as result of the material in this publication can be accepted

By Darshan publishers or the author / editor

ISBN: 978–81–931973–8–7

Published by Darshan Publishers.

Rasipuram, Namakkal Dt., Tamilnadu.

This book is meant for educational and learning purposes. The author(s) of the book has/have taken all reasonable care to ensure that the contents of the book do not violate any existing copyright or other intellectual property rights of any person in any manner whatsoever. In the event the author(s) has/have been unable to track any source and if any copyright has been inadvertently infringed, please notify the Publisher in writing for corrective action.

iii

SHANMUGA INDUSTRIES ARTS AND SCIENCE COLLEGE (CO-ED)

TIRUVANNAMALAI

Lion S. Karthikeyan, B.com., MJF Secretary & Correspondent

Message I feel immense pleasure to note that Shanmuga

Industries Arts and Science College, an emerging

institution has initiated a remarkable attempt by

organizing a challenging State Level Seminar on

Innovative Trends in Physics (ITP-2016). It is my

privilege to highlight a few words of mine wishing the seminar and its proceedings.

Research is an action connected with the creation or innovation of fresh

processes, methods or services and using the newly discovered knowledge to

discharge a society or market need. Research must always be high value in order to

generate knowledge that is applicable outside of the research setting with

implications that go beyond the group that has participated in the research.

I believe that on the day stay here will create a spark in every participants’

mind to attain innovate some amazing stuffs in their carrier. Also I would like to

extend my wholehearted appreciation to all the organizers of this seminar for having

instigated and taken untiring endeavors to make this event an incredible one.

I wish the seminar to reap the rewards of great success.

Lion S. Karthikeyan, B.com., MJF

iv

Prof. AL. Udayappan, M.Sc., M.Phil., FICS.,

Academic Dean

Foreword It is a great pleasure to know that Shanmuga

Industries Arts and Science College, an emerging

institution has put forth a step forward by

organizing a challenging state level seminar on

Innovative Trends in Physics (ITP- 2016). I feel

honoured to pen a few words of mine wishing the

seminar.

Education is a medium of learning in which knowledge and skills of people

are reassigned from one generation to the next through teaching and research.

Further, scientific research is a generally used measure for judging the reputation of

an academic institution. I am very much happy that the staff and students of this

department of physics have realized the importance of this practice and they have

taken a unique initiative in organizing this state level seminar. I strongly believe that

this seminar is an arena to bring students’ and scholars’ inborn abilities and

endeavors to make realize their hidden skills. Also I hope that this seminar will

provide the correct platform for the researchers to get awareness on the latest trend in

the field of physics.

I wish each and every participant to make use of this opportunity to reach

their milestones and to make the event a memorable one. Also I express my heartfelt

appreciation to the organizers for having taken tireless efforts towards the success of

this event.

Prof. AL. Udayappan

v

Dr. K. Anandaraj, Ph.D.,

Principal

Foreword I am delighted to appreciate the organizing committee

members of the Department of Physics for bringing

out the proceeding of State Level Seminar entitled

Innovative Trends in Physics (ITP – 2016). This seminar is a benchmark and the result of

series of academic celebrations held in this regard. This

really encourages many innovative thickness to review

their positions in new research in scientific context. The outcome of this seminar has

been so enchanting that it would create enormous awareness and intellectual exercise

in this progressive field. Let this attempt be ennobling process of growth.

I once again congratulate the Head of the department of Physics for his

strenuous efforts to capture the essence of the state level seminar.

Good Luck

Dr. K. Anandaraj

vi

Mr. S. Arumugam, M.Sc., M.Phil.,

Convener & Head of Physics

Preface We, the organizing committee, extend our sincere

thanks to Shanmuga Industries Arts and Science

College for granting permission to organize the State

Level Seminar on Innovative Trends in Physics (ITP

– 2016) on 10th March 2016.

There are two invited talks by the experts and

38 contributed papers from various colleges. This

proceeding comprised of all the contributed papers. The special theme for this

seminar has been selected based on the current trends. More than 50 papers have

been reviewed and 38 papers have been accepted for oral presentation. The

following are the core areas under which the selected papers are categorized

Bio materials

Nanoscience and Nanotechnology

Crystallography

Acoustics

Semiconductor physics and Devices

Laser physics and Applications

Multifunctional Nanomaterials

Materials science

spectroscopy

We are highly grateful to the invited speakers, Dr. D. Sastikumar, Professor

of Physics, NIT, Trichy and Dr. R. T. Rajendrakumar, Associate Professor of

Physics, Bharathiar University, Coimbatore for having accepted our invitations to

make the event as a successful one. This State Level seminar is the outcome of

sincere and hardwork of so many hands and minds.

S. Arumugam

Convener & Head of Physics

ITP-2016

vii

ABOUT THE COLLEGE

Shanmuga Industries Arts and Science College, popularly known as SIASC,

is a Co-educational institution promoted by Shanmuga Industries Educational

Trust, Tiruvannamalai. The objective of the Trust is to enable the college into an

institution of excellence and to let the rural youth living in and around

Tiruvannamalai to have easy access to higher education. The college is situated in

Tiruvannamalai on the Tiruvannamalai-Manalurpet state highway. The premier

institute of college education was established in the year 1996. Since it’s founding,

SIASC has distinguished itself by providing a higher level of culture, cultivating

good discipline and finer value of life among students. SIASC, is one among the

leading institutions in the country to have been certified under section 2(f) of the

UGC Act 1956 and awarded with ISO 9001:2000 certificate and in recognition of

its quality standards. The facilities and infrastructure that the institution has, is

much above the benchmark propounded by the University.

ABOUT THE DEPARTMENT OF PHYSICS

The Department of Physics was established in the year 2004 with a view to

foster scientific temper among the students, to develop an independent thinking to

achieve their goal and to provide education at the Bachelor level in Basic science.

M.Sc., Physics and M.Phil., physics course was started in the year of 2012 and

2013 for the benefit of physics graduates. Since then 09 batches of B.Sc Physics,

02 batches of M.Sc., Physics and 02 batches of M.Phil., Physics students have

successfully completed their degree courses. The department has a team of well

qualified and experienced fourteen teaching faculties and two non teaching staff.

viii

ORGANIZING COMMITTEE

Secretary & Correspondent - Lion Mr. S. Karthikeyan, B.Com., MJF

Treasurer - Mr. S.D.R.S. Babu

Academic Dean - Prof. Al.Udayappan, M.Sc.,M.Phil.,FICS.,

Principal - Dr. K. Anandaraj

Convener - Mr. S. Arumugam, Head of Physics

Co-Convener - Mr. S. Vasudevan, Asst. Prof., Physics

INVITATION / REGISTRATION / RECEPTION COMMITTEE

Ms. V.K. Bhavanisathya - Coordinator, Asst. Prof., Physics

Ms. G. Nathiya - Asst. Prof., Physics

Mrs. Sudhalakshimi - Asst. Prof., Physics

PROGRAMME COMMITTEE

Mr. G. Lakshiminarayanan - Coordinator, Asst. Prof., Physics

Mr. K. Manivannan - Asst. Prof., Physics

PROCEEDING COMMITTEE

Mr. D. Gopinath - Coordinator, Asst. Prof., Physics

Mr. D. Arunkumar - Asst. Prof., Physics

CERTIFICATE COMMITTEE

Mr. D. Rajendiran - Coordinator, Asst. Prof., Physics

Mr. P.Mani - Asst. Prof., Physics

CATERING COMMITTEE

Mr. T. Ramamoorthy - Coordinator, Asst. Prof., Physics

Mr. P. Maniselvan - Asst. Prof., Physics

Mr. D. Siva - Asst. Prof., Physics

ix

Contents

S.NO. PAPER TITLE PAGE

NO.

1

2

3

4

5

6

7

8

9

THERMOACOUSTICAL STUDIES ON THE BINARY MIXTURES OF METHYL

AND ETHYL ACETATE IN 2-METHOXYETHANOL AT DIFFERENT

TEMPERATURES

G. Ravichandran and D.Gopinath

APPLICATION OF FT-IR SPECTROSCOPY TO STUDY THE

MINERALOGICAL COMPOSITION ON COASTAL SEDIMENTS FROM EAST

COAST OF TAMILNADU, INDIA

J.Chandramohan, M.Tholkappian, G.Elango and R.Ravisankar

ACOUSTICAL STUDIES ON THE EFFECT OF ELECTROLYTES ON THE

MICELLIZATION OF SODIUM CAPRYLATE AT 303.15 K

S.Arumugam and S.Maria Antony Pragash

ULTRASONIC STUDIES ON THE EFFECT OF ALCOHOLS ON THE MICELLATION

OF LITHIUM DODECYL SULPHATE IN AQUEOUS SOLUTION

G. Lakshiminarayanan and A.Anithadevi

GROWTH AND CHARACTERIZATION OF MORPHOLINIUM PERCHLORATE

A.Arunkumar , P. Ramasamy

GROWTH, STRUCTURAL, SPECTROSCOPIC, THERMAL AND HARDNESS

STUDIES OF CESIUM SULFAMATE SINGLE CRYSTAL

S.Rafi Ahamed and P.Srinivasan

INTRAMOLECULAR WEAK HYDROGEN BONDS IN SOME SIX AND FIVE

ATOM INTERACTIONS: SPECTROSCOPIC ANALYSIS

D.Nandha kumar and V.Periyanayagasami

GROWTH AND CHARACTERIZATION OF BIS THIOUREA POTASSIUM ACID

PHTHALATE (BTKAP) SINGLE CRYSTALS

N. Jhansi, K. Mohanraj and D. Balasubramanian

GROWTH, STRUCTURAL, THERMAL, AND MECHANICAL PROPERTIES OF

SUCCINIC ACID DOPED POTASSIUM HYDROGEN PHTHALATE (KHPSA)

CRYSTAL

R. Aruljothi, R. U. Mullai, E. Vinoth, M. Sheik Muthali, S. Vetrivel

1

11

23

31

39

43

56

65

72

x

10

11

12

13

14

15

16

17

18

19

GROWTH AND IN-VITRO STUDIES ON CYSTINE URINARY STONE IN

SILICA GEL MEDIUM

M.Saravana Kumar and F.Liakath Ali Khan

CHARACTERIZATION AND THEORETICAL PROPERTIES OF DIHYDROXY

COUMARIN, NLO SINGLE CRYSTAL BY DFT METHOD

K.Sambathkumar , R.saradha, A.Claude and K.Settu.

GROWTH AND CHARACTERIZATION OF POTASSIUM THIOCYANATE

DOPED POTASSIUM DI HYDROGEN ORTHO PHOSPHATE (KSCN-KDP)

CRYSTALS BY SR METHOD

B.Shalini

STRUCTURAL AND OPTICAL STUDIES OF WOLFRAMITE METAL

TUNGSTATES (M2+ WO4; M=CO & NI SYNTHESIZES VIA SONOCHEMICAL

PRECIPITATION TECHNIQUE

A.Sampathu, K. Ravichandran

EFFECT OF FE ON CERIUM OXIDE NANOPARTICLES

A.AArthi, P. Vijayashanthi, S. Shanmuga Sundari

GROWTH AND CHARACTERIZATIONS OF (TRI) GLYCINE BARIUM

CHLORIDE SINGLE CRYSTAL FOR OPTOELECTRONICS AND PHOTONICS

APPLICATIONS

S. Chennakrishnan, D. Sivavishnu, T. Kubendiran, S.M. Ravi Kumar

MEASUREMENT OF NATURAL RADIOACTIVITY AND ASSESSMENT OF

RADIOLOGICAL HAZARDS IN COASTAL SEDIMENTS OF CUDDALORE

COAST, TAMILNADU, INDIA

K. Thillaivelavan, N. Harikrishnan, G. Senthilkumar, R. Ravisankar

SYNTHESIS AND CHARACTERIZATION OF NANO ALUMINA BY TOP DOWN

APPROACH

S.Vasudevan and P. Kavithamani

ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON THE

MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION AT FIXED

FREQUENCY 2 MHZ AND FIXED TEMPERATURE OF 303.15K.

G. Lakshiminarayanan and D. Arun kumar

NMR , NBO, AND VIBRATIONAL SPECTROSCOPIC ANALYSIS OF

O-NITROBENZAMIDE

D.Nandha kumar, P.Mani

82

87

102

110

120

127

136

146

154

159

xi

20

21

22

23

24

25

26

27

28

EFFECT OF ANNEALING PROCESS ON STRUCTURAL, MORPHOLOGICAL,

ELECTRICAL AND OPTICAL PROPERTIES OF CEO2 NANOPARTICLES

SYNTHESIZED BY CHEMICAL PRECIPITATION METHOD

K. Mohanraj, D. Balasubramanian, N. Jhansi, R. Suresh, C. Sudhakar

SYNTHESIS AND CHARACTERIZATION OF PURE AND L-ALANINE DOPED

AMMONIUM DIHYDROGEN PHOSPHATE(ADP)

R. Deepika, P. Meena

NOVEL SYNTHESIS ROUTE OF Γ- GLYCINE SINGLE CRYSTAL IN THE

PRESENCE OF 2-AMINOPYRIDINE POTASSIUM CHLORIDE FOR

OPTOELECTRONIC APPLICATIONS

R. Srineevasan

STRUCTURAL AND OPTICAL PROPERTIES OF ZINC OXIDE/MAGNESIUM

OXIDE (ZNO/MGO) NANOCOMPOSITES SYNTHESIZED BY THE FACILE

PRECIPITATION PROCESS

D. Siva , K. Anandan

ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON THE

MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION AT FIXED

FREQUENCY 2 MHZ AND FIXED

TEMPERATURE OF 303.15K.

G. Lakshiminarayanan and D. Arun kumar

SYNTHESIS, GROWTH, STRUCTURE, OPTICAL, AND PHOTOCONDUCTING

PROPERTIES OF AN INORGANIC NEW NONLINEAR OPTICAL CRYSTAL:

SODIUM MANGANESE TETRA CHLORIDE (SMTC)

M. Packiyaraj, D.Sivavishnu, G.J. Shanmuga Sundar and S. M. Ravi Kumar

SYNTHESIS, STRUCTURAL, OPTICAL AND MORPHOLOGICAL PROPERTIES

OF (Co, Ag) doped ZINC OXIDE NANOPARTICLES

J.Balavijayalakshmi , K.Meena

ASSESSMENT OF HEAVY METAL POLLUTION IN COASTAL SEDIMENTS OF

EAST COAST OF TAMILNADU USING ENERGY DISPERSIVE X-RAY

FLUORESCENCE SPECTROSCOPY (EDXRF)

N. Harikrishnan, M. Suresh Gandhi, Durai Ganesh, A. Chandrasekaran, R. Ravishankar

SYNTHESIS, GROWTH AND PHYSICOCHEMIC AL PROPERITIES OF

DIAMMONIUM TETRACHLORO ZINCATE NLO CRYSTALS (DTCZ)

S.M.Ravikumar and G.Nathiya

169

180

186

202

211

216

225

231

248

xii

29

30

31

32

33

34

35

36

37

38

VARIATIONAL ITERATION METHOD FOR BURGER EQUATION

M.Sudhalakshmi, R.Sivakumar

GROWTH AND CHARACTERIZATION OF L-ALANINE MIXED BISTHIOUREA

CADMIUM BROMIDE(LABTCB) CRYSTAL

A. Maniselvan and T.Kubendiran

ULTRASONIC STUDIES ON THE EFFECT OF DMSO AND DMF ON THE

MICELLIZATION OF LITHIUM DODECYL SULPHATE

IN AQUEOUS SOLUTIONS

G. Lakshiminarayanan and R. Kumaresan

GROWTH AND CHARACTERIZATION OF BISTHIOUREA MANGANESE

SULPHATE SINGLE CRYSTAL BY SLOW EVAPORATION METHOD

H. Poornima

GROWTH AND PHYSICOCHEMICAL PROPERTIES OF A NEW

SEMIORGANIC NONLINEAR OPTICAL MATERIAL THIOUREA

POTASSIUM HYDROGEN PHTHALATE FOR NLO APPLICATIONS

A.Anbarasi, R.Srineevasan, M. Packiyaraj and S.M.Ravi Kumar

SOLUTION OF COUPLED NONLINEAR EQUATION BY

VARIATIONAL ITERATION METHOD

M.Sudhalakshmi, R.Sivakumar

ULTRASONIC STUDIES ON THE EFFECT OF DIOXANE AND

TETRAHYDROFURAN ON THE MICELLIZATION OF CETYL

TRIMETHYL AMMONIUM BROMIDE IN AQUEOUS SOLUTIONS

G. Lakshiminarayanan and D.Sakthivel

SYNTHESIS, GROWTH AND CHARACTERIZATION OF Cd2+ DOPED ZTS

CRYSTALS

J.Rajeswari

THERMAL AND ACOUSTICAL STUDIES ON SOME LIQUID ALKALI

METALS

P. Ramadoss, V. K. Bhavanisathya

HYDROTHERMAL SYNTHESIS OF CERIUM OXIDE NANO PARTICLES

P.Vijayashanthi, A.Aarthi, S. Shanmuga Sundari

257

268

276

282

288

296

311

317

323

330

1

THERMOACOUSTICAL STUDIES ON THE BINARY MIXTURES OF

METHYL AND ETHYL ACETATE IN 2-METHOXYETHANOL

AT DIFFERENT TEMPERATURES

G. Ravichandran* and D.Gopinath 1

* Post-Graduate and Research Department of Physics

Aringar Anna Government Arts College, Villupuram-605 602 1 Post-Graduate and Research Department of Physics

Shanmuga Industries Arts & Science College, Thiruvannamalai.

ABSTRACT

Density and ultrasonic velocity have been measured in the binary liquid

mixtures of methyl acetate (MA) and ethyl acetate (EA) in 2-methoxyethanol (2ME)

over the temperature range from 303.15 K to 323.15 K. The measured data are used

to compute the excess thermodynamic parameters namely excess adiabatic

compressibility (βsE), excess intermolecular free length (Lf

E) and excess molar

volume (VE). A plot of these excess thermodynamic parameters against the mole

fraction of methyl acetate and ethyl acetate over the entire composition range shows

a negative deviation indicating a strong interaction between the component

molecules of liquid mixtures. The results are discussed in terms of formation of

hydrogen bonding between the component molecules of the liquid mixtures.

Keywords: ultrasonic velocity, excess adiabatic compressibility, excess free length,

excess molar volume, hydrogen bonding.

1. Introduction:

The nature and the relative strength of the molecular interaction between the

component molecules of liquid mixtures have been successfully investigated by

many authors using ultrasonic method [1-9]. This is mainly due to the fact that the

ultrasonic velocity measured in pure liquids or liquid mixtures is fundamentally

related to the binding forces between atoms or molecules of a given liquid and

between the component molecules in the case of liquid mixtures. The excess

thermodynamic parameters calculated in liquid mixtures at various temperatures can

also provide information on the nature and degree of interaction between the

component molecules of the liquid mixtures. The deviation of excess thermodynamic

2

parameters with composition from its ideal behaviour gives a deep insight into the

various other dynamic processes that occur in the solutions [10-19].

In the present paper, we report on the results of nature of molecular interactions

between the molecules of the binary mixtures of methylacetate (MA) and

ethylacetate (EA) in 2-methoxyethanol (2ME) using excess thermodynamic

parameters like excess adiabatic compressibility (βsE), excess intermolecular free

length (LfE) and excess molar volume (VE) respectively in the temperature range

303.15 - 323.15 K.

2. Materials and method

The chemicals used in the present work are spectroscopic (SR) grade with a

minimum assay of 99.9 %. These chemicals were purchased from SD Fine

chemicals, India. The purity of the chemicals is checked by recording the IR

spectrum of each of these chemicals and comparing it with the standard spectrum

available in the literature. In all systems studied, the various compositions of the

binary liquid mixtures were prepared in terms of mole fraction.

The density and ultrasonic velocity were measured as a function of

composition of the binary mixtures at 303.15, 308.15, 313.15, 318.15 and 323.15 K

respectively.

The density of pure liquids and their liquid mixtures are measured using a

dilatometer of 20 ml capacity with the dilatometer immersed in a temperature

controlled water bath (accuracy ±0.01°). The accuracy in the measurement of

density of pure liquids and their liquid mixtures is ±2 parts in 104.

The ultrasonic velocity of the liquid mixtures has been measured using a

Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-Microsystems Pvt. Ltd.,

Chennai, India) in the temperature range of 303.15 - 323.15 K by circulating water

from a thermostatically controlled water bath and the temperature being maintained

to an accuracy of ±0.01°.

Using the measured values of ultrasonic velocity and density, various excess

thermodynamic parameters such as excess adiabatic compressibility (βsE), excess

free length (LfE) and excess molar volume (VE) have been calculated using the

equations,

3

calsE

s 12 (1)

where

2211 sXsXcals

calff

Ef LLL 12 (2)

where

2211 ffcalf LXLXL

(3)

where

12

2211

MXMXVobs

2

22

1

11

MXMXVcal

where M1, M2, X1, X2, ρ1, ρ2, ρ12, βs1, βs2, βs12 , Lf1, Lf2 , Lf12 are the molecular

weight, mole fraction, density, adiabatic compressibility and intermolecular free

length of the components 1 and 2 and their mixtures respectively.

All the excess thermodynamic parameters were fitted to Redlich-Kister

equation

N

j

jj

E XAXXY1

11121 )12( (4)

and the parameters Aj-1 were computed using least square fit method.

3. Results and Discussion:

The ultrasonic velocity measurements are carried out in the binary mixtures of

methyl acetate-2methoxyethanol (MA-2ME) and ethyl acetate-2methoxyethanol

(EA-2ME) at different temperatures. The experiment was carried out in the

composition range of X1=0 to 1 mole fraction of methyl and ethyl acetates. The

measured density and the density values reported in the literature for methyl acetate,

ethyl acetate and

2-Methoxyethanol are given in Table1.

Using the measured values of ultrasonic velocity and density for the binary

mixtures of MA-2ME and EA-2ME are calculated and are presented in Tables 2 & 3.

calobsE VVV

4

The coefficients of equation (4) viz., A0 to A3 computed for βsE, LfE and VE by least

square fitting method along with the standard deviations (σ) are given in Tables 4 &

5. The variation of excess thermodynamic parameters such as excess adiabatic

compressibility (βsE), excess freelength (LfE) and excess molar volume(VE) with

increasing concentration of methyl and ethyl acetates (X1 = 0 to 1 mole fraction) are

shown in figures 1-6.

3.1 Methyl acetate – 2 Methoxyethanol system (MA-2ME):

Figure 1 shows that the excess adiabatic compressibility at 303.15 K has a

negative deviation for the entire concentration range of methyl acetate. The

magnitude of negative deviation reaches a maximum at X1=0.4983 mole fraction of

MA and then becoming less and less negative with further increase in concentration

of MA in 2ME. The excess free length and excess molar volume also exhibits a

similar behaviour as that of excess adiabatic compressibility at 303.15 K. The

observed negative deviation of βsE, LfE and VE at 303.15 K from the ideal behaviour

can be explained as follows;

Generally, liquid mixtures which show non-linearity in ultrasonic velocity

with concentration can be analysed in terms of excess thermodynamic functions.

This is due to the fact that the excess thermodynamic functions are found to be

sensitive towards the mutual interactions between the component molecules of the

liquid mixture. In ideal mixtures, the physical property of the mixture may be

evaluated as a sum of fractional contribution from the individual components. But,

non-ideal mixtures show considerable deviation from linearity in their physical

property with respect to concentration and these have been interpreted as arising due

to strong or weak interactions. The sign and the extent of deviation of these

functions from ideality depend on the nature of constituents and composition of the

mixtures [20,21].

The negative deviation exhibited by excess adiabatic compressibility at

303.15 K becomes increasingly negative reaching a maximum at X1= 0.4983 mole

fraction of MA. This may be due to increasing strength of interaction between the

components of liquid mixture. The greater negative deviation of βsE for MA-2ME

system suggests that a specific molecular interaction is likely to operate between

2ME and MA molecules leading to the formation of a complex. In MA-2ME

5

system, 2ME is a highly associated liquid and MA is highly polar and also a proton

acceptor. Hence, in the present binary mixture MA-2ME, in general the interaction

responsible for association may be likely due to hydrogen bonding, dipole-dipole

interactions or formation of complexes due to charge transfer. In MA-2ME system,

the complex formation may be through hydrogen bonding between 2ME and MA

molecules. From the structure of the molecules of the constituents, it can be inferred

that the oxygen atom of carbonyl group (C=O) of MA may be involved in O-H---O

bonding with the hydroxyl group (OH) of 2ME molecule with the strength of

bonding becoming maximum at X1= 0.4983 mole fraction of MA . The present

study is supported by the ultrasonic studies carried in the binary mixtures of

dimethylsulphoxide - acetone carried out by Syal et al [22], and in some monohydric

alcohols in dimethylsulphoxide carried out by Palani et al [23].

LfE at 303.15 K also shows negative deviation for the entire composition

range of MA showing maximum negative deviation at X1 =0.4983 mole fraction of

MA (Figure.2). The negative deviation in LfE indicates that ultrasonic waves cover a

longer distance due to decrease in intermolecular free length describing the dominant

nature of hydrogen bonding between unlike molecules of the binary mixture. A

similar type of studies was reported by Rajagopal and Chenthilnath [15] in the binary

mixtures of 2- methyl-2 propanol in acetophenone.

The excess molar volume (VE) for MA-2ME system in the temperature range

studied also shows a negative deviation for the entire composition range of MA with

the maximum negative deviation occurring at X1= 0.4983 mole fraction (Figure 3).

The changes in VE is influenced by two factors namely,

(i) loss of dipolar association and differences in size and shape and

(ii) dipole-dipole, dipole-induced dipole interaction, charge transfer

complexation and hydrogen bonding between unlike molecules.

The former effect leads to expansion in volume and the latter contributes a

contraction in volume. The actual value of VE depends on the balance between these

two opposing contributions [24]. Large negative values of VE indicate strong

interaction between unlike molecules [11]. Such a large negative deviation in VE is

observed in the present MA-2ME system. The greater negative deviation is due to

the formation of hydrogen bonding between 2ME and MA molecules.

6

As the temperature is increased to 308.15, 313.15, 318.15 and 323.15 K, the

maximum negative deviation of βsE, LfE and VE further increases and is more

pronounced at 323.15 K compared to their values in other temperatures respectively.

This indicates that the complex formation is more favoured at 323.15 K rather than

at other temperatures. This can be explained as follows:

At 303.15 K, 2ME is self associated through hydrogen bonding. At higher

temperatures due to thermal agitation, self associated 2ME molecules are disrupted,

and this facilitates the interaction between 2ME and MA molecules through the

formation of intermolecular hydrogen bonding. Thus, at a higher temperature of

323.15 K, probably the interaction is stronger than that at other temperatures. This

observation is further supported by the conclusions drawn by Chauhan et al. [25], in

their ultrasonic velocity studies carried out in the binary mixtures of acetonitrile-

propylene carbonate in the temperature range 298 K – 318 K. The interaction

between acetonitrile and propylene carbonate molecules becoming stronger at 318 K

than at 298 K.

3.2 Ethyl acetate – 2Methoxyethanol system(EA-2ME):

In EA-2ME system, the variation of excess thermodynamic functions βsE, LfE

and VE at all temperatures studied are shown in Figures 4-6. All these excess

parameters show a negative deviation for the entire composition range of EA (X1=0-

1 mole fraction) and for the temperature range studied. The negative deviation of

βsE, LfE and VE increases with increase of temperature showing maximum deviation

at 323.15 K. The magnitude of negative deviation reaches a maximum at X1=0.5463

mole fraction of EA and then becoming less and less negative with further increase

in concentration of EA in 2ME.

The negative deviation of βsE, LfE and VE observed in EA-2ME system at all

the temperatures studied is similar to that in MA-2ME system, so the explanation

offered for MA-2ME system is equally applicable to EA-2ME system. The negative

deviation of βsE , LfE and VE increases with increase of temperature reaching a

maximum at 323.15K. This indicates that the complex formation is much stronger at

323.15 K.

7

0.0 0.2 0.4 0.6 0.8 1.0-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1Figure 1

MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K

Molefraction of methylacetate (X1)

(sE )

X10

-11 m

2 N-1

0.0 0.2 0.4 0.6 0.8 1.0-2.6

-2.4

-2.2

-2.0

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2Figure 2

MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K

Molefraction of methylacetate (X1)

( L fE )

x 1

0-12 m

8

0.0 0.2 0.4 0.6 0.8 1.0-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1Figure 3

MA + 2ME at 303.15 K MA + 2ME at 308.15 K MA + 2ME at 313.15 K MA + 2ME at 318.15 K MA + 2ME at 323.15 K

Molefraction of methylacetate (X1)

(VE )

x10-7

m3 m

ol-1

0.0 0.2 0.4 0.6 0.8 1.0-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5Figure 4

EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K

Molefraction of ethylacetate (X1)

(sE )

X10

-11 m

2 N-1

9

0.0 0.2 0.4 0.6 0.8 1.0

-1.0

-0.8

-0.6

-0.4

-0.2

0.0Figure 5

EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K

Molefraction of ethylacetate (X1)

( L fE )

x 1

0-12 m

0.0 0.2 0.4 0.6 0.8 1.0

-6

-5

-4

-3

-2

-1

0 Figure 6

EA + 2ME at 303.15 K EA + 2ME at 308.15 K EA + 2ME at 313.15 K EA + 2ME at 318.15 K EA + 2ME at 323.15 K

Molefraction of ethylacetate (X1)

(VE )

x10-7

m3 m

ol-1

10

4. Conclusion: The excess thermodynamic functions such as βsE, Lf

E and VE are calculated for the binary mixtures of methyl acetate-2methoxyethanol and ethyl acetate-2 methoxyethanol in the temperature range 303.15 K – 323.15 K. All these parameters show negative deviation in the composition range X1= 0-1 mole fraction of methyl acetate and ethyl acetate in 2-methoxyethanol and at all the temperatures studied. Both the binary mixtures show a maximum negative deviation at 323.15 K indicating that the complex formation is much stronger at this temperature. In the binary mixtures studied, the formation of complexes is due to the formation of hydrogen bonding between the oxygen of carbonyl group (C=O) of methyl acetate, ethyl acetate with the hydroxyl group (OH) of 2-methoxyethanol. References :

[1] A Kumar, Colloids and Surfaces, 34 313 (1989) . [2] J D Pandey, G P Dubey, B P Shukla, S N Dubey, Pramana J. Phys. 37 443(1991) [3] S L Oswal, R P Phalak, J. Sol. Chem. 22 43 (1993) . [4] T M Aminabhavi and K Banerjee K. J. Chem. Eng. Data, 43 (1998) 514. [5] Krzyszt of Bebek, Mole. Quant. Acous., 26 15 (2005) [6] Anil Kumar Nain, Bull. Chem.Soc. Jpn, 79 1688 (2006) [7] S Ravichandran and K Ramanathan , Poly. Plast. Tech Engg, 47 169 (2008). [8] G Arul and L Palaniappan , Ind. J Pure. Apple Phys. 43 755 (2005). [9] G Parthiban, G Arivazhagan, M Subramanian and T Thenappan, Physics and Chem.,of Liqs, 49(1) ( 2011). [10] G Ravichandran and K Govindan , Indian J Pure & Appl Phys, 32 852 (1994) [11] G Ravichandran and K Govindan , J Sol Chem., 25 75 (1996) . [12] Eduardo J M Filipe, Luis F G Martins , Jorge C.G.Calado Clare Mccabe and George Jackson, J.Phys.Chem., B, 104 1322 (2000). [13] A toumi, N Hafaiedh and M Bouanz, Fluid Phase equilibria, 278 68 (2009). [14] G Nath & R Palikary , Indian J Phys, 83 (9) 1309 (2009) . [15] K Rajagopal and S Chenthilnath , Indian J Pure & Appl Phys, 48 326 (2010) . [16] Gyan Prakash and Dubey Krishnakumar,Thermochimica Acta, 524 7 ( 2011). [17] Harishkumar, Rajendrakumar and Dheeraj, K. J. Pure. Appl.&Indus. Phys, 1(4) 260 (2011). [18] S Elangovan and S Mullainathan Indian J. Phys. 86 727 (2012) [19] G Arivazhagan, M Mahalakshmi and SAJ Zahira Indian J. Phys. 86 493 (2012) [20] R J Fort and H Moore , Trans Faraday Soc, 61 2102 (1965) . [21] R J Fort and H Moore , Trans Faraday Soc, 62 1112 (1966) . [22] Syal V K Chauhan and S Uma Kumari, Indian J Pure & Appl Phys, 43 844 (2005) [23] R Palani , S Saravanan and R Kumar , Rasayan J Chem, 2 (3) 622 (2009) . [24] A Krishnaiah , D N Rao and P R Naidu , Polish J Chem, 55 2633 (1981) . [25] M S Chauhan , K C Sharma , S Gupta , M Sharma & S Chauhan , Acoustic Letters, 18 233(1995) . [26] “Spectroscopic Identification of Organic Compounds” by Robert Silverstein M, Clayton Bassler G & Terence Morrill C, John Wiley & Sons, New York (1981).

11

Application of FT-IR Spectroscopy to study the Mineralogical Composition on

Coastal Sediments from East Coast of Tamilnadu, India

J.Chandramohan1, M.Tholkappian2, G.Elango3 and R.Ravisankar4

1Department of Physics, E.G.S. Pillay Engineering College, Nagapattinam –

611002, Tamilnadu, India 2Department of Physics, Sri Vari College of Education, Tiruvannamalai, 606611,

Tamilnadu, India 3Post Graduate and Research Department of Chemistry, Government Arts College,

Tiruvannamalai-606603, Tamil Nadu, India 4Post Graduate and Research Department of Physics, Government Arts College,

Tiruvannamalai-606603, Tamil Nadu, India

E-Mail: ravisankarphysics@gmail.com

ABSTRACT

FT-IR spectroscopy has recently received attention for its potential use in

quantitative mineral analysis. The Fourier Transform Infrared (FT-IR) absorption

spectra of sediments contain more information about mineralogy. In the present

study, coastal sediments collected from Pattipulam to kaipanikuppam along the East

Coast of Tamilnadu is subjected to mineral analysis using FT-IR technique. From the

infra spectrum, the minerals are identified from the location or band position of

peaks with the help of available literature. The infrared analyses of sediment samples

indicate the presence of quartz, microcline, orthoclase, albite, kaolinite,

montmorlinite, calcite, aragonite and organic carbon. Among the different minerals

quartz is present invariably in all the samples. The accessory minerals are identified

as kaolinite, montmorlinite, calcite and aragonite from the i.r. study. FT-IR

technique gives the useful information about the mineralogical composition of the

sediments.

Keywords: Sediment, Mineral Analysis, FT-IR spectroscopy

1.0. INTRODUCTION

Sediments are complex mixtures of inorganic and organic components.

Analysis of sediments provides environmentally significant information. Sediment

12

plays a predominant role in aquatic radioecology and plays a role in accumulating

and transporting contaminants within the geographic area. Sediment composition is

determined by their source and biotic transformations with respect to time [1].

Coastal sediments usually act as sinks of river borne metals released through

weathering and human activities in terrestrial environments [2-4].

The mineral analysis in sediment is one of the key researches for geologist to

identify the heavy minerals in coastal areas. There are number of techniques

available for the mineral identification over a decade. Among the number of

techniques FT-IR is a potential tool for mineral analysis due to its non-destructive

and rapid analysis. FT-IR spectroscopy can provide detailed information on organic

and inorganic constituents of sediment records. FT-IR is used to identify various

chemical groups including functional group present in the mineral constituents of the

sediments and also alternative method for acquiring quantitative mineralogy. FT-IR

spectroscopy has certain advantages such as requirement of small quantity of sample,

fast and easy method of sample preparation and short time to analysis.

In the present study, a mineralogical investigation on coastal sediment

samples from Pattipulam to kaipanikuppam of East coast of Tamilnadu has been

carried out using FT-IR technique. The study area presents a great interest because of

the manufacturing unit, mini industries, chemical industries etc.

2.0 MATERIALS AND METHODS

2.1 Sample Collection

Sediment samples were collected along the Bay of Bengal coastline, from

Pattipulam to kaipanikuppam coast during pre-monsoon condition. Sampling

locations were selected to collect representative samples from all along the study

area. Table 1 represents the geographical latitude and longitude for the sampling

locations at the study area. In order to ensure minimum disturbance of the upper

layer, samples were collected by a Peterson grab sampler from 10 m water depths

parallel to the shoreline. The grab sampler collects 10 cm thick bottom sediment

layer from the seabed along the 11 stations. Each sample of about 2 kg was kept in a

thick plastic bag and transported to the laboratory. The collected from different sites

under study were labeled as PPM, DVN, MAM, KKM, KPM, VPC, TPM, MKM,

13

OKM, APT and KPK. The distance between each station falls around 10kms. The

location map is given in Fig. 1.

Table -1 Latitude and longitude of Locations

S. No Sample ID Latitude(N) Longitude(E) Location

1 PPM 12°40'51.27"N 80°15'19.35"E Pattipulam

2 DVN 12°39'19.32"N 80°14'49.68"E Devaneri 3 MAM 12°37'55.53"N 80°14'13.14"E Mahabalipuram 4 KKM 12°34'56.33"N 80°13'22.37"E Kokilamedu 5 KPM 12°30'57.52"N 80°11'50.57"E Kalpakkam 6 VPC 12°27'58.97"N 80°11'16.29"E Veppancheri 7 TPM 12°24'42.28"N 80° 9'48.29"E Thenpattinam 8 MKM 12°21'26.51"N 80° 6'52.67"E Mudaliyarkuppam 9 OKM 12°19'35.89"N 80° 5'44.70"E Odiyurkuppam

10 APT 12°16'19.80"N 80° 3'16.00"E Alampara fort

11 KPK 12°12'42.65"N 80° 1'32.40"E Kaipanikuppam

Fig 1-Location Map of the Study area

14

2.2 Sample Preparation and Analysis

The KBr pellet technique was followed by mineral analysis. A sample of 2

mg is mixed with 40 mg of spectroscopic KBr in the ratio 1:20 using a mortar and

pestle. Before mixing, the necessary amount of KBr powder is dried at 120°C for 6

hours in an oven. Otherwise the broad spectral peak due to free OH will seriously

affect the interpretation of the bound hydroxyls associated, with any of the mineral.

The major and minor minerals are qualitatively determined by FT-IR technique. For

each samples the spectra were taken in the mid region of 4000-400cm-1. Such

coverage range ensures that most of the useful vibrations active in the IR will be

included. The instrument scans the spectra 16 times in 1 minute and the resolution is

5cm .This instrument is calibrated for its accuracy with the spectrum of a standard

polystyrene film. Every time, before the spectrum of sample is obtained; the

spectrum of the polystyrene film is taken and checked for the accuracy and

transmittance. The best spectrum for each site was considered as a representative

spectrum of the site. The typical FT-IR spectrum is shown in Fig. 2.

Fig. 2. A Representative FT-IR spectrum of coastal sediment sample

15

Table 2 FT-IR observed absorption bands (cm-1) of coastal sediment

samples of East Coast of Tamilnadu with mineral identifications

Silicate

Mineral Feldspar Clay Minerals

CARBONATE

MINERALS Sample

ID Quartz

Micro

cline

Ortho

clase Albite

Kaoli

nte

Montm

orlinite

Orga

nic

Carbo

n Calci

te

Argaon

ite

PPM

459, 695,

778, 795,

1616,

1875

425,

460,

535,

642

432,

467,

536, 580

485,

420,

575,

785,

990

935,

1030,

3420

876,

1640

2854,

2926

715,

1414

,

1795

855,

1475

DVN

455, 695,

780,

1080,

1875

427,

462,

645,

742

537, 584 787,

990

471,

3425

480,

1640

2850,

2930

715,

1420

1460,

1790

MAM

455, 695,

775,

1616,

1875

464,

586,

640

469, 536 405,

420

3425,

1030

3140,

1640

2851,

2925

715,

878,

2515

856,178

8

KKM

455, 695,

775,

1082,

1875

428,

464,

534,

643,

742

469, 583

579,

787,

995

939,

3425,

1030

480,

875

2854,

2929

875,

1795

1476,

1790

KPM 458, 697,

779, 1873

428,

461,

534,

640

467,

1040,

581, 648

405,

422,

990,

1095

475,

1030,

1115,

3420

1643,

3441

2851,

2925

1412

,

1795

1785

VPC

460, 775,

795,

1080,

1875

463,

587,

640,

1051

584, 650

525,

785,

990,

1095

1030,

920,

475

1645,

3440 2857

715,

1416 855

16

TPM

458, 695,

776,

1082,

1616,

1873

462,

642

435,

467,

540, 581

420,

785,

993

920,

3425

480,

826

2855,

2930

715,

875,

2515

1460,17

89

MKM

695, 775,

1085,

1615,

1875

428,

462,

590,

640

538,

1040

575,

785,

1095

940,

1030,

3425

478,

878

2852,

2925

715,

1417

,

1798

855,

1785

OKM

457, 780,

795,

1085,

1620

426,

644,

1060

536,

648,

1011,

1040

405,

420,

575

939,

3425

1640,

3433 2929

875,

1418

1480,

1790

APT

455, 698,

1085,

1620,

1875

430,

534,

643

469,

538, 584

790,

425,

995

427,

1030,

1115

1643,

1445

2855,

2926

715,

1795

855,178

5

KPK

455, 655,

7751,

108, 1875

463,

587,

640

434,

466,

536, 582

405,

420,

575

1030,

3425

480,

825

2854,

2926

715,

1420

,

2515

855,

1460,

1790

3.0. RESULTS AND DISCUSSION

The absorption frequencies of the peaks in the spectra of each site in wave

number unit (cm-1) are reported in Table 2. By comparing the observed frequencies

with available literature [5-11], the minerals such as quartz, microcline, orthoclase,

albite, Kaolinite, montmorlinite, calcite and aragonite have been identified. The

mineral wise discussion is outlined is given below.

3.1. Quartz

Quartz is a silicate mineral. It forms most abundant mineral in the Earth’s

crust. It is present in many sediments as well as sedimentary and igneous rocks. The

IR absorption peaks of quartz were reported by many workers [12-16]. The presence

17

of IR absorption bands at 1870-1875, 1615-1620, 1080-1085, 795-800,775-780, 695-

700, & 455-460 cm-1 indicate quartz in all samples and it is presented in Table 2.

The pattern of absorption in quartz can be explained by ascribing the 455cm-1

region (Si-O asymmetrical bending vibrations), the band in the region 695cm (Si-O

symmetrical bending vibrations), the bands in the region 775cm (Si-O symmetrical

stretching vibrations) and 795cm (Si-O symmetrical stretching vibrations).

For any samples, minimum four to maximum six peaks are observed.

The characteristic feature of quartz is doublet appearing at or around 800 cm-1and

780cm-1. Such a clear observation of doublet was noticed in the samples PPM, VPC

& OKM and any of these peaks was noticed in remaining samples. The peak

appearing at 695 cm-1 is most useful to determine the nature of the mineral with

regard to the structural stability. Many workers have calculated the crystallinity

index of quartz using the symmetrical bending vibration of Si-O group obtained at

695 cm-1. The 695 cm-1 is present in most of the samples indicate that quartz mineral

are well in crystalline form. Band assignments for different minerals of coastal

sediment samples are given in Table 3.

3.2. Feldspar

Around 60% of the Earth's crust is made up of feldspar; the feldspars are a

group of minerals that have similar characteristics due to a similar structure. The

general formula for feldspar can be given as WZ4O8in which W may be a Na, K, Ca,

and /or Al. Chemically the feldspar is silicates of aluminum containing sodium,

potassium, iron, calcium or barium or combinations of these elements. Feldspar is

found in association with all rock types including granite, gneiss, basalt and other

crystalline rocks and constituents of the most igneous rocks. It crystallize from

magma in both intrusive and extrusive rocks; they occur as compact minerals, as

veins, and are also present in many types of metamorphic rock. They are also found

in many types of sedimentary rocks. Feldspar weather to yield a large part of clay

found in soils. The feldspar group of minerals was analyzed by FT-IR technique and

reported by many workers [13-21]. From the Table 2, the i.r. absorption peaks

appearing at 405-410, 420-425, 425-430, 430-435, 460-465, 465-470, 535-540, 575-

18

580, 580-585, 585-590, 640-645, 645-650, 720-725, 740-745, 765-770, 785-790,

990-995, 1010-1015, 1040-1045 & 1050-1055cm-1 was assigned to feldspar mineral.

The peaks appearing at 465-470cm-1, 535-540cm-1 & 640-645 belong to Si-O-

Si bending, Si-O asymmetrical bending vibration and Al-O coordination vibration

respectively.

3.2.1. Microcline

The presence of microcline is identified by the peaks at 425-430, 460-465, 530-

535, 585-590, 640-645, 740-745 & 1050-1055 cm-1.

3.2.2. Orthoclase

The peaks at 430-435, 465-470, 535-540, 580-585, 645-650,765-770,

1010-1015 & 1040-1045cm-1 are observed for Orthoclase in the Samples.

3.2.3. Albite

The observed peaks of albite are 405-410, 420-425, 575-580, 720-725, 785-790

& 990-995cm-1.

3.3. Clay Minerals

Clay minerals are very common in fine grained sedimentary rocks such as

shale, mudstone, and siltstone and in fine grained metamorphic slate and phyllite.

Clay minerals are common weathering products (including weathering of feldspar)

and low temperature hydrothermal alteration products. Clay minerals include Kaolin

group which includes the minerals kaolinite, dickite, halloysite, and nacrite

(polymorphs of Al2Si2O5(OH)4) and Smectite group which includes dioctahedral

smectites such as montmorillonite and nontronite and trioctahedral smectites like

saponite. The presence of kaolinite and montmorillonite indicate clay minerals in

samples.

Kaolinite is a mineral with a chemical composition Al2Si2O5. It is layered

silicate mineral, with one tetrahedral sheet linked through oxygen molecules to one

octahedral sheet of alumina octahedral. Kaolinite mineral is crystallizing in the

monoclinic system and forming the chief constituent of china clay and Kaolin. It is

softly, earthy, usually white mineral, produced by weathering of feldspars. It is a

hydrous aluminum silicate commonly formed by weathering and decomposition of

rocks containing aluminum silicate compounds; feldspar is a chief source. Kaolinite

19

is the basic raw material for ceramics and large quantities are also used in the

manufacture of coated paper.

The IR absorption peaks of kaolinite are reported by many workers [22-26].

The observed peaks at 470-475, 935-940, 1030-1035, 1115-1120 & 3420-3425 cm-1

are attributed to kaolinite. The broad absorption band observed at 1030 cm-1 belongs

to Si–O stretching of kaolinite (clay mineral) [18-19].

Montmorillonite is a very soft phyllosilicate mineral that typically forms in

microscopic crystals, forming clay. Chemically it hydrated sodium calcium

aluminium magnesium silicate hydroxide(Na.Ca)x(AlMg)2(Si4O10)(OH)2.nH2O.

Montmorillonite, a member of the smectite family is 2:1 clay, meaning that it has 2

tetrahedral sheets sandwiching a central octahedral sheet. It is the main constituent of

the volcanic ash weathering product, bentonite.

The observed i.r absorption bands at 475-480, 875-880, 1640-1645 and

3440-3445 cm-1 in the spectrum of the samples suggested the presence of

montmorilinite in the samples [13, 8, 15, 16, 20]. The band typically centered at

3400cm-1 is due to O-H stretching of water molecule present in the interlayer region

of montmorillonite. The strong peak observed at 1635 cm-1 in the samples suggests

the possibility of water of hydration in the adsorbent.

3.4. Carbonate Minerals

Carbonates are commonly deposited in marine settings when the shells of dead

planktonic life settle and accumulate on the sea floor. This class also includes the

nitrate and borate minerals. Many workers have reported that i.r absorption band

appearing at 2982, 2519, 1795, 1410, 1433, 875 & 715cm-1 is assigned to calcite

[2.4-5. 7-8, 11, 16, 18, 19, 23]. The calcite shows the i.r. absorption bands appearing

at 2515, 1795, 1410, 875cm-1 & 715cm-1 in the samples. From Table 2, the IR

absorption bands at 855-860, 1455-1460, 1475-1480, & 1785-1790cm-1 are found to

be aragonite [4-5. 8, 11, 14, 19].

3.5. Organic Carbon

The weak absorption bands present at 2925-2930 and 2850-2855 cm-1 suggest

the presence of organic carbon in the samples [15-16, 20]. These bands are due to C-

20

H absorption of contaminants present in the samples. This band belongs to carbon

and oxygen double bonded linkage (C=O).

4.0. CONCLUSION

FT-IR spectroscopic analysis performed on the coastal sediment samples

taken from Pattipulam to kaipanikuppam of East coast of Tamilnadu India allowed to

identify the constituents of minerals. The FTIR study indicates presence of quartz,

microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and

organic carbon in soils. Among the various observed minerals, quartz, feldspar and

kaolinite are major and others are trace on the basis of their presence and intensities

of corresponding peaks. The performed analyses provided useful information about

the mineralogical composition of the sediments. This is a fundamental step in

gaining knowledge about the constituent of minerals. The FT-IR technique was

highly useful in identifying different minerals in sediment. The FT-IR approach with

respect to the traditional one is tremendous due to preparation.

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14. Russell JD. Infrared methods. A Hand Book of Determinative Methods in

Clay Mineralogy, Wilson, M. J.(Ed.,) Blackie and Son Ltd. New york, 11-67.

15. Ravisankar R, Kiruba S, Naseerutheen A, Chandrasekaran A, MaheswaranC.

Estimation of firing temperature of Ancient potteries of Tamilnadu, India by

FT-IR Spectroscopic technique. Der Chemica Acta. 2011;2;157.

16. Ravisankar R, Eswaran P, Rajalakshmi A, Chandrasekaran A, Dhinakaran B.

Beach rock from the South East Coast of Tamilnadu, India. A Spectroscopic

study, Advances in Applied Science. 2012;3:95

22

17. Hlavay J, Jonas K, Elek S, Inczedy J. Characterization of the particle size and

the crystallinity of certain minerals by infrared spectrophotometry and other

instrumental methods- II. Investigation on quartz and feldspar. Clay and Clay

Minerals. 1978;26:139.

18. White JL. Interpretation of infrared spectra of soil minerals. Soil Science.

1971;112:22 Ghosh SN. Infrared spectra of some selected minerals, rocks and

products. Journalof Material Science. 1978;13:1877.

19. Ghosh SN. Infrared spectra of some selected minerals, rocks and products.

Journal of Material Science. 1978;13:1877.

20. Ravisankar R, Kiruba S, Chandrasekaran A, Naseerutheen A, Seran M, Balaji

PD. Determination of firing temperature of some Ancient Potteries of

Tamilnadu, India by FT-IR Spectroscopic Technique. Indian Journal of

Science and Technology. 2010;3:1016.

21. Ravisankar R, Chandrasekaran A, Kiruba S, Senthilkumar G, Maheswaran C.

Analysis of Ancient Potteries of Tamilnadu, India by Spectroscopic

Techniques. Indian Journal of Science and Technology. 2010;3:858

22. Neog AK, Boruah RK, Sahu OP, Borah PC, Ahmed W, Boruah GD. XRD

and IR of Deopani clay. Asian. Chemical Letters. 1999;3:172.

23. Xu Z, Cornilsen BC, Popko DC, Penning WD, Wood JR, Hwang JY.

Quantitative mineral analysis by FT-IR spectroscopy. International Journal of

Vibirational Spectroscopy. 2001;5:4.

24. Crowley JK, Vergo N. Near- infrared reflectance of mixtures of kaolin group

minerals; use in clay. Clay and Clay Minerals. 1988;36:310.

25. Oinuma K, Hayashi H. Infrared study of mixed layer clay minerals, American

Minerals. 1965;50:1213.

26. Bukka K, Miller JD, Shabtai J. FT-IR study of deuteratedmontmorillonites:

structural features relevant to pillared clay stability. Clay and Clay Minerals.

1992;40:92.

23

ACOUSTICAL STUDIES ON THE EFFECT OF ELECTROLYTES ON THE

MICELLIZATION OF SODIUM CAPRYLATE AT 303.15 K

S.Arumugam1and S.Maria Antony Pragash2

1,2Post-Graduate and Research Department of Physics,

Shanmuga industries arts and science college, thiruvannnamalai.

ABSTRACT

Ultrasonic velocity, density and viscosity studies have been carried out in

aqueous solutions of sodium caprylate containing 0.1 - 0.5 M electrolytes (LiCland

KCI) in the molar concentration range of 0.05-0.50 M. These studies are carried out

in sodium caprylate concentration range of 0.05-0.50 M at a fixed frequency of

2MHz and at a fixed temperature of 303.15K. The variation of ultrasonic velocity in

aqueous solutions of sodium caprylatecontaining 0.1 - 0.5 M electrolytes (LiCl and

KCI) with the sodiumcaprylateconcentration exhibit a break at critical micelle

concentration (CMC). Experimental data have been used to estimate the adiabatic

compressibility (β), apparent molar volume (ɸv), apparent molar compressibility (ɸk)

and specific viscosity (ŋsp).The result are discussed in terms of structure making or

structure breaking effect of electrolytic solution in the mixtures .The results are

discussed in terms of formation of sodium caprylatemicelles through hydrophobic

interaction and hydrogen bonding.

INTRODUCTION

Molecular interaction in liquid mixtures has been the subject of numerous

investigation in recent past years. Effects of temperature on the micelle formation of

anionic surfactants in the presence of different concentrations of urea have been

reported by Sandeep Kumaret al.[1].Here one of the attempts is undertaken to

investigate, the effect of electrolytes such as (LiCl and KCl) on the micellization of

surfactant (sodium caprylate) in aqueous medium which is more important because

the electrolytes play the important role on surfactant.

The values of density, ultrasonic velocity, and viscosity, observed ultrasonic

absorption,adiabatic compressibility, apparent molar volume apparent, apparent

24

molar compressibility with molar concentration of sodium caprylate in aqueous and

aqueous – electrolytes (LiCl and KCI) mixtures of various compositions at a fixed

frequency of 2 MHz and fixed temperature of 303.15 K are also given in figures 1-

12. The aim our present investigation is to determine ultrasonic studies on the

effect of electrolytes (LiCl and KCI) on the micellization of sodium

caprylatein aqueous solutions at fixed frequency of 2 MHz and fixed

temperature of 303.15 k. The results are interpreted in terms of formation of sodium

caprylate(NaC)micelles in the solutions.

MATERIALS AND METHODS

The surfactant namely sodium caprylate(NaC) and electrolytes(liCl&KCl)

used in present study are of AR/BDH grade purchased from Merck specialties

private limited, India. They are used as such without further purification and all

chemical having a purity of ≥99%. Millipore water having a specific conductance of

2.3×10-6 S m-1 is used in preparing the stock solution of electrolytes and surfactant.

Aqueous solutions of surfactant containing different concentration of electrolytes of

electrolytes (0.05 - 0.50 M) are prepared by adding concentration stock solution of

electrolytes. All the measurements are carried out in the surfactant concentration of

0.05 - 0.50 M. Ultrasonic velocity and absorption studies are fixed frequency of 2

MHz in the surfactant concentration range 0.05-0.50 M. Ultrasonic velocity and

absorption measured using a digital ultrasonic pulse echo velocity meter at a fixed

temperature of 303.15 K.

The experimental part comprises of determination of density (ρ), viscosity

(ηs), and observed ultrasonic absorption (α). Using these fundamental parameters the

various other parameters such as adiabatic compressibility (β), apparent molar

volume(ɸv), apparent molar compressibility (ɸk) and specific viscosity (ηsp) can be

computed.

RESULT AND DISCUSSIONS

From the measured values of ultrasonic velocity (U), viscosity (ηs), and

observed ultrasonic absorption (α), adiabatic compressibility (β), apparent molar

25

volume (ɸv), apparent molar compressibility (ɸk) and specific viscosity (ŋsp) were

computed and shown in graphically in figures (1-12). Apparent molar volume (ɸv)

calculated from density data for aqueous solutions of NaC and aqueous sodium

caprylate (NaC) containing 0.1 - 0.5 M electrolytes (LiCl and KCl) is found to be

negative for the entire concentration range of surfactant as shown in figures 1 - 2.

Also, the values of apparent molar volume (ɸv) increases (becomes less negative)

with increase of NaC concentration for each concentration of electrolytes. The

addition of electrolytes to aqueous solutions of NaC shifts the CMC towards the

lower concentration side of surfactant. With further increase in the concentration of

electrolytes added the CMC shifts more towards lower concentration side of NaC.

The addition of electrolytes (LiCl and KCl) not only decrease the CMC of ionic

surfactants [2] by screening the electrostatic repulsion between the polar head groups

and also restrict the movement of the hydrophobic surface of the surfactant

molecules away from aqueous environments. As a result, less electrical work is

required in the formation of surfactant micelles. This is responsible for the shift of

the CMC towards lower concentration side of NaC respectively in the presence of

electrolytes. These results obtained from the present studies are in good agreement

with the observations made by Chauhanet al.[2] in aqueous solutions of SDS

containing LiCl and KCl.

From the figures 3 - 6 it can be seen that the ultrasonic velocity measured in

aqueous solution of surfactant (NaC) containing different concentration of

electrolytes increases with increasing concentration of surfactant. The Na+ ion

obtained due to the dissociation of NaC in aqueous medium may contribute towards

the increase of ultrasonic velocity by increasing cohesion in the medium by its water

structure making property.In addition the aggregation of NaC molecules with

counter ions at the interface may also increase the cohesion among water molecules

at the interface leading to an increase of ultrasonic velocity.Water molecules from

hydrogen bonds with the carboxylate group of NaC. The hydrogen bond formations

also contribute for the increase in ultrasonic velocity.The increase of ultrasonic

velocity when the concentration of NaC is increased beyond CMC may be due to the

26

aggregation of NaC molecules leading to micelle formation [3]. Above CMC,

aggregation of molecules occurs by hydrogen bonding. The formation of higher

aggregates through hydrogen bonding leads to an increase of ultrasonic velocity in

the medium.

In the present studies, the ultrasonic velocity measured in aqueous solutions

of NaC containing different concentrations of electrolytes is found to be in the order:

KCl<LiCI. This is due to the difference in the electrostriction effect produced by the

cations namely Li+ and K+ of these electrolytes in the surrounding medium. The

results obtained from the ultrasonic velocity and adiabatic compressibility studies of

the present work is in good agreement with the results of patilet al.[4] carried out in

aqueous solutions of sodium dodecyl sulphate with electrolytes.

The apparent molar compressibility (ɸk) obtained for aqueous NaC with

electrolytes in the entire concentration range of surfactant (NaC) studied are found to

be negative as shown in figures 7 - 8 for any particular concentration of each

electrolyte, the apparent molar compressibility of aqueous solutions of both

surfactant increases (become more negative) with increasing concentration of

surfactant as shown in figures 7 - 8. The negative values of apparent molar

compressibility (ɸk) indicate that three is an increase in the amount of structured

water present in the medium. This may be due to the ionic hydration of Li+, K+ ions

and hydrophobic hydration of NaC anions The increase (more negative) in the values

of apparent molar compressibility with increase in the concentration of each

electrolyte (LiCl&KCl) at a particular concentration of surfactant may be due to the

increased ionic hydration of cations of the electrolytes. These result in an increase of

internal pressure which in turn leads to lowering of compressibility of the solutions.

i.e. the solution becomes header to compress.

From the figures 9-10 the Specific viscosity in aqueous solution of

surfactant (NaC) and aqueous solutions of sodium caprylate (NaC) containing 0.1 -

0.5 M of electrolytes (LiCl and KCl) increases with increasing concentration of

surfactant.The CMC values obtained from Specific viscosity studies for aqueous

solution of surfactant containing 0.1 - 0.5 M electrolytes in agreement with the CMC

27

values obtained from molar volume. When the electrolytes are added to aqueous

surfactant solution, it disrupts the existing solvent structure and forms a new and

thermodynamically more feasible arrangement [5-7].As a result, the water molecules

are tightly bound to each other due to the more hydrophobic nature of sodium

caprylate ions and hydrophilic nature of electrolytic cations in the medium. This

invariably results in the increase of specific viscosity in the medium as observed in

the present work

The observed ultrasonic absorption (α/f2) in aqueous solutions of surfactant

(NaC) and aqueous solution of sodium caprylate (NaC) containing electrolytes

increases with increasing concentration of surfactant as shown in figures 11-12

Moreover, the observed absorption is found to be several time higher than the

classical absorption. This indicates that the observed absorption is not the observed

absorption. Water monomers present in the medium can form by hydrogen bonds

with carboxylate groups of NaC. The increase of cohesion in the solutions leads to

increase in ultrasonic absorption.When NaC is dissolved in water, it dissociated into

cation (Na+ ions) and anions (sodium caprylate). Na+ ions thus obtained restrict the

overall freedom of water molecules by its water structure making property. This

increases the cohesion among the water molecule, thus leading to increasing of

ultrasonic absorption.When electrolytes are dissolved in aqueous solutions of

surfactant (NaC) due to the dissociation of electrolytes, cations such as Li+, K+ and

Cl- anions along with sodium caprylate anions are obtained. Moreover, the ionic

hydration formed around Li+ and K+ ions also contributes towards the increased

cohesion among the water molecules in the medium leading to an increased in

observed ultrasonic absorption. In the presence of hydrophobic sodium caprylate

ions, the solvent- solvent interactions are strengthened due to strong hydrophobic

hydration. This makes the surrounding water molecules to be very closely packed;

this in turn increases the observed ultrasonic absorption in the medium.

The CMC values of aqueous NaC and aqueous solutions of sodium caprylate

(NaC) having different concentration of electrolytes(LiCl&KCl) in the order: 0.35

M for aqueous NaC0.33, 0.30, 0.27 M for aqueous with 0.1 – 0.5 M LiCl. 0.32,

28

0.28, 0.25 M for aqueous with 0.1 – 0.5 M KCl.Ultrasonic velocity, adiabatic

compressibility (β), apparent molar volume (ɸv), apparent molar compressibility (ɸk)

and specific viscosity (ŋsp).The result are discussed in terms of structure making or

structure breaking effect of electrolytic solution in the mixtures.

CONCLUSION

In the present study, apparent molar volume apparent molar compressibility

values are found to be negative in aqueous solution of Sodium caprylate and aqueous

solution of NaC with electrolytes. Ultrasonic velocity in aqueous solution of

surfactant (NaC) and aqueous solution of NaC with electrolytes increases with

increasing concentration of NaC and electrolytes. The apparent molar volume (ɸv) is

negative values with addition of each of 0.1- 0.5 M (LiCl and KCl)to aqueous

solution of NaC, the CMC shifts towards lower concentration side. The extent of

shifting of CMC towards lower concentration side of surfactant by the anions of

electrolytes depends on degree of counter ion binding to the micelles. The observed

ultrasonic absorption in aqueous solution of sodium caprylate with electrolytes is due

to the ionic and hydrophobic hydration in the medium. Formation of hydrogen bonds

between water molecules and the carboxylate groups of surfactant also contributes

for the observed increase in ultrasonic absorption.

Figure – 1 Figure – 2

0.2 0.3 0.4 0.5 0.6 0.7-0.16-0.15-0.14-0.13-0.12-0.11-0.10-0.09-0.08-0.07-0.06-0.05-0.04-0.03-0.02-0.010.00

0.35 M

0.32 M0.27 M

0.25 M

App

aren

t mol

arvo

lum

e (

v) m

3 mol

-1

Square root of molar concentration of sodium caprylate (C)1/2mol dm-3

NaC+waterNaC+water+0.1 M kClNaC+water+0.3 M kClNaC+water+0.5 M kCl

0.2 0.3 0.4 0.5 0.6 0.7

-0.050

-0.045

-0.040

-0.035

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.33 M

0.27 M

0.30 M

0.35 M

App

aren

t mol

arvo

lum

e (

v) m3 m

ol-1

Square root molar concentration of sodium caprylate (C)1/2 mol dm-3

NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl

29

0.0 0.1 0.2 0.3 0.4 0.51520

1525

1530

1535

1540

1545

1550

1555

1560

1565

0.28 M

0.25 M

0.32 M

0.35 M

Ultr

ason

ic v

eloc

ity

(U)

m s-1

Molar concentration of sodium caprylate (c) mol dm-3

NaC+waterNaC+water+0.1 M KClNaC+water+0.3 M KClNaC+water+0.5 M KCl

0.0 0.1 0.2 0.3 0.4 0.51520

1525

1530

1535

1540

1545

1550

1555

1560

1565

1570

1575

0.30 M0.27 M

0.33 M

0.35 M

Ultr

ason

ic v

eloc

ity (U

) m s-1

Molar concentration of sodium caprylate concentration (C) mol dm-3

NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl

Figure – 3 Figure– 4

Figure – 5 Figure – 6

Figure – 7 Figure – 8

0.0 0.1 0.2 0.3 0.4 0.54.05

4.10

4.15

4.20

4.25

4.30

0.28 M

0.25 M

0.35 M

0.32 M

Adi

abat

ic co

mpr

essib

ility

(s)

X 1

0-10 N

-1 m

2

Molar concentration of sodium caprylate (C) mol dm-3

Nac + waterNaC + water + 0.1 M kClNaC + water + 0.3 M kClNaC + water + 0.5 M kCl

0.0 0.1 0.2 0.3 0.4 0.54.024.044.064.084.104.124.144.164.184.204.224.244.264.284.304.324.34

0.27 M

0.30 M

0.33 M

0.35 M

Adi

abat

ic co

mpr

essib

ility

(s)

X 1

0-10 N

-1 m

2

Molar concentration of sodium caprylate concentration (c) mol dm-3

NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl

0.2 0.3 0.4 0.5 0.6 0.7-8.5-8.0-7.5-7.0-6.5-6.0-5.5-5.0-4.5-4.0-3.5-3.0-2.5-2.0-1.5-1.0-0.50.00.5

0.25 M

NaC + WaterNaC + water + 0.1 M KClNaC + water + 0.3 M KClNaC + Water + 0.5 M KCl

0.28 M0.32 M

0.35 M

App

aren

t mol

ar co

mpr

essib

ility

(k)

X 1

0-8 m

3 mol

-1 P

a-1)

Square root of molar concentration of sodium caprylate (C)1/2mol dm-3

0.2 0.3 0.4 0.5 0.6 0.7

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

0.35 M

0.33 M

0.30 M

0.27 M

App

aren

t Mol

ar c

ompr

essi

bilit

y (

v) X

10-8

m3 m

ol-1 P

a-1

Square root 0f molar concentration of sodium caprylate (c)1/2mol dm-3

NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl

30

Figure – 9 Figure – 10

Figure – 11 Figure – 12

REFERENCES

1.Sandeep Kumar, PunamYadav, Dinkar Malik and Vijai Malik InternationalJournalofTheoretical &AppliedSciences6(1): 43-49, (2014)

2. L.zang,P.Somasundram,C.Maltesh,Langmuir 12 (1996)2371.

3. M.K.Rawat,Sangeeta, Ind .J.Pure& appl.Phys.46(2008)187. 4 .D.G.Oakenfull,L.R. Fisher,J.phys.Chem.81(1977)1838 5. C.S.Patil, B.R.Arbad,Asian J.Chem.15(2003)655. 6. A.P.Mishra, Ind.J.Chem.43A(2004)730. 7. Monalisa Das, S.Das, A.K.Patnaik, J.phys.Sci.24 (2013)37.

0.2 0.3 0.4 0.5 0.6 0.70.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.28 M

0.25 M

0.32 M

0.35 M

Spec

ific

visc

osity

(sp

/ C1/

2 )

Square root of molar concentration of sodium caprylate (c)1/2 mol dm-3

NaC+waterNaC+water+0.1 M KClNaC+water+0.3 M KClNaC+water+0.5 M KCl

0.2 0.3 0.4 0.5 0.6 0.7

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.30 M

0.27 M

0.33 M 0.35 M

Spec

ific

visc

osity

(sp

/ c1/

2 )

Square root of molar concentration of sodium caprylate (c)1/2 mol dm-3

NaC+waterNaC+water+0.1 M liClNaC+water+0.3 M liClNaC+water+0.5 M liCl

0.0 0.1 0.2 0.3 0.4 0.5

2050

2100

2150

2200

2250

2300

2350

2400

2450

2500

2550

0.35 M

0.32 M

0.25 M

0.28 M

Obs

erve

d ul

trra

soni

cabs

orpt

ion

( /

f2 ) X 1

0-15

Np

m-1 s2

Molar concentration of sodium caprylate (C) mol dm-3

NaC + waterNaC + water + 0.1 M KClNaC + water + 0.3 M KClNaC + water + 0.5 M KCl

0.0 0.1 0.2 0.3 0.4 0.5

2050

2100

2150

2200

2250

2300

2350

2400

2450

2500

2550

2600

2650

2700

2750

0.27 M

0.30 M

0.33 M

0.35 M

Obs

erve

d ul

tras

onic

abs

orpt

ion

(f2 ) X

10-1

5 Np

m-1 s2

Molar concentration of sodium caprylate (c) mol dm-3

NaC+waterNaC+water+0.1 M LiClNaC+water+0.3 M LiClNaC+water+0.5 M LiCl

31

ULTRASONIC STUDIES ON THE EFFECT OF ALCOHOLS ON THE

MICELLATION OF LITHIUM DODECYL SULPHATE

IN AQUEOUS SOLUTION

G. Lakshiminarayanan1 and A.Anithadevi2

1,2 Post-Graduate and Research Department of Physics

Shanmuga Industries Arts and Science College,Thiruvannamalai.

Abstract

Acoustical studies are undertaken in required amount of LDS with the

addition of various proportions of alcohols [ME, ET] at various concentrations

ranging from 5mM to 13mM at 303.15 K. From the measured values of velocity,

density, and viscosity various other parameters such as compressibility, free length,

free volume and internal pressure are calculated and reported. The results indicate

that the ultrasonic velocity of ethanol is lightly higher than methanol for all aqueous

and aqueous alcoholic mixture because of due to their chain length difference.

Keywords: Ultrasonic velocity, Compressibility, LDS, Free length

INTRODUCTION

Amphiphilic molecules like surfactants exhibit several special properties,

such as critical micelle concentration (CMC), aggregation number, size and shape of

the micelle and degree of micelle dissociation, because of their ability to undergo co-

operative and non-co-operative aggregation in aqueous system. Such properties are

modified by the addition of substances such as, salts or non electrolytes (alcohols,

urea, amine etc.)[1-4].These additives can affect in many ways to delicate balance of

hydrophilic and hydrophobic interactions of micelle forming surfactants.

Considerable attention has been paid in recent years to the influence of alcohols on

ionic micellar structures, partly because they are the co-surfactants most commonly

employed in the preparation of micro emulsions. In the present investigation

ultrasonic method is used for obtaining dynamic information and reactions occurring

in the aqueous micellar solutions of Lithium dodecyl sulphate in the presence of

alcohols.

EXPERIMENTAL TECHNIQUES

The experimental solutions are prepared by the required amount of Lithium

dodecyl sulphate is dissolved in de ionized water for the preparation of concentration

32

range of 3mM - 12mM. The 5%, 10%, 15% and 20% of Methanol (ME), Ethanol

(ET) with Lithium dodecyl sulphate (LDS) in aqueous solutions are prepared in the

concentration range of 3mM - 12mM. The velocity of ultrasonic waves in the

solution have been measured using digital ultrasonic pulsed echo velocity meter

(model no: VCT – 70A, Vi Micro Systems Pvt. Ltd, Chennai) work at a fixed

frequency of 2 MHZ and fixed temperature of 303.15k. The values of density and

shear viscosity of different concentrations were measured using specific gravity

bottle and Ostwald’s viscometer respectively. All the measurements were carried out

at 303.15 K by maintaining the temperature constant by circulating water from a

thermostatically controlled water bath.

COMPUTATIONS OF PARAMETERS

Adiabatic compressibility (βs), intermolecular free length (Lf), free volume

(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),

respectively.

βs = 1/C2ρ (1)

Lf = KT βs 1/2 (2)

Vf = (M C / K η)3/2 (3)

πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)

where, c is ucltrasonic velocity, ρ is density, KT is temperature dependant constant,

M is effective molecular weight, K is constant for liquids, b is constant, T is

temperature.

RESULT AND DISCUSSION

In the present study, the ultrasonic velocity, density and viscosity

measurements were carried out in aqueous solution of LDS with addition of alcohols

[Methanol and Ethanol] at different concentrations. The values of velocity (U),

density (ρ) and viscosity (η) with molar concentration of lithium dodecyl sulphate in

aqueous and aqueous – alcoholic mixtures of various compositions measured for a

fixed frequency of 2 MHz and fixed temperature of 303.15 K. The values of

Adiabatic Compressibility, Free length, Free Volume and Internal Pressure with

33

molar concentration of lithium dodecyl in aqueous and aqueous – alcoholic mixtures

of various compositions at a fixed frequency of 2 MHz and fixed temperature of

303.15K.

Ultrasonic velocity studies of lithium dodecyl sulphate in aqueous solutions

The variations of ultrasonic velocity against concentration of lithium

dodecyl in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic

velocity increases with increasing concentration of lithium dodecyl sulphate in

aqueous solutions and exhibits sharp break at a particular concentration is known as

Critical Micellar Concentration (CMC) which is confirmed by Chanchal das etal [5] .

The increase in ultrasonic velocity can be explained as follows. 1) When the lithium

dodecyl sulphate is added in aqueous solvent, lithium dodecyl dissociates Na+ ions

and dodecyl sulphate ions. Na+ ion restrict the mobility of the water

molecules.2)The lithium dodecyl sulphate ions making hydrogen bond with water

molecules.3) The micelle formation in aqueous solution of lithium dodecyl sulphate

and higher aggregation leads to increase in velocity beyond the CMC.All the above

mentioned effect contributes the increase in velocity before and after CMC.

The measured ultrasonic velocity increases with increasing concentration of

lithium dodecyl sulphate in aqueous – alcoholic solvent (5-20%V/V of ME &ET)

mixtures of solution and exhibits sharp break at a particular concentration of lithium

dodecyl sulphate (i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity

is due to the alcoholic solvents act as a structure breaker in aqueous lithium dodecyl

sulphate. So,this is leads to restricting the mobility of the water molecules by lithium

ions. The micelle formation in aqueous-alcoholic solution of lithium dodecyl

sulphate and higher aggregation leads to increase in velocity after CMC of solution.

In addition to average dielectric constant of lithium dodecyl sulphate in the solution

also contributes increase in ultrasonic velocity. The velocity observed in aqueous-

alcoholic solvent at particular compositions (volume by volume) in the order:

Velocity of 5% ME mixture < Velocity of 10 % ME mixture < Velocity of 15 % ME

mixture < Velocity of 20 % ME mixture.

Similarlly, the same explanation observed for LDS with aqueous-ethanol systems.

34

In addition, the presence of alcoholic (Co – Solvent) affect the compressibility

of the medium by disrupting the ordered water structure present around the

hydrophobic and hydrophilic surfaces of LDS molecules in order to form hydrogen

bonding with water molecules. This strengthens the aqueous – alcohol solvent

interaction by the way of releasing structured water present around the ions of

lithium dodecyl sulphate. This might be responsible for the decreasing of

compressibility (Fig.5&6) by addition of alcohols.

From the figure 1, it is observed that when the 5% V/V of methanol is added

to the aqueous solution of lithium dodecyl sulphate, the CMC of aqueous solution of

lithium dodecyl sulphate shifted towards the higher concentration side (8.4 mM).

This is due to the lowering of the average dielectric constant of the medium because

of the dielectric constant of water is greater than methanol.

Similarly, when the 10-20% V/V of methanol is added to the aqueous solution

of lithium dodecyl sulphate the CMC of aqueous solution of lithium dodecyl

sulphate shifted towards the higher concentration side in the order of (8.9 mM), (9.5

mM), (10 mM), respectively. For ethanol systems observed CMC valuesin the

order: 8.7, 9.3, 9.8 and 10.5Mm, respectively.

Viscosity studies of lithium dodecyl sulphate in aqueous and aqueous –

alcoholic mixtures:

The variations of viscosity are shown in Figs. 3 & 4. The ultrasonic viscosity

increases with increasing concentration of lithium dodecyl sulphate in all the

systems are studied. This is due to the increasing viscous force within the medium.

So this leads to further increasing of ultrasonic viscosity with increasing

concentration of lithium dodecyl sulphate . .

Free length of lithium dodecyl sulphate in aqueous and aqueous – alcoholic

mixtures:

The variation of ultrasonic velocity in a solution depends on the

intermolecular free length on mixing. On the basis of a model for sound propagation

proposed by Eyring and Kincaid et al [6]. Ultrasonic velocity increases on

decreasing of free length and vice versa. Intermolecular free length is a predominant

35

factor in determining the variation of ultrasonic velocity in fluids and their solutions.

In the present investigation, it has been observed that intermolecular free length

decreases linearly on increasing concentration of lithium dodecyl sulphate in

aqueous and aqueous – alcoholic mixtures and exhibits sharp break at CMC as

shown in Figs.7 & 8.

This indicates significant interaction between solute – solvent molecules,

solvent – solvent molecules and suggesting ionic hydration of solvent molecules on

solute. As expected, adiabatic compressibility decreases with increasing

concentration of lithium dodecyl sulphate in all aqueous – alcoholic mixtures and

may be due to their increasing larger portion of solvent molecules being

electrostricted and the amount of bulk solvent decreases.

Free Volume of lithium dodecyl sulphate in aqueous and aqueous – alcoholic

mixtures:

The variations of free volume against concentration of lithium dodecyl

sulphate in aqueous and aqueous – alcoholic mixtures are shown in Figs. 9 & 10.

In aqueous solutions of lithium dodecyl sulphate , the free volume decreases with

increasing concentration of lithium dodecyl sulphate . This observation gives the

information of solvent molecules accommodate around the solute. Therefore, the

further increasing of concentration of lithium dodecyl sulphate suggested the

increase of volume in the solution. So the corresponding free volume decreases.

The above explanation theory is applicable for all the aqueous and aqueous –

alcoholic mixtures of lithium dodecyl sulphate solution.

Internal Pressure of lithium dodecyl sulphate in aqueous and aqueous –

alcoholic mixtures:

The internal pressure is the most important deciding factor for aqueostical

studies. In the present studies, the variation of internal pressure against the

concentration of in aqueous and aqueous – alcoholic mixtures as shown in Figs.

11 & 12. The internal pressure increases with increasing concentration of lithium

dodecyl sulphate in all the systems are studied. This suggests that there is a

significant interaction between the solute and solvent molecules. So the internal

36

0.004 0.006 0.008 0.010 0.012 0.0141490

1495

1500

1505

1510

1515

1520

1525

1530

1535

1540

1545

1550

Ultr

ason

ic v

eloc

ity c

(m s

-1 )

Molar concentration of LDS X ( mol dm-3)

water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS

0.004 0.006 0.008 0.010 0.012 0.014

1500

1510

1520

1530

1540

1550

1560

1570

1580

1590

Ultr

asoi

c ve

losi

ty C

(ms-1

)

Molar concentration of LDS X (mol dm-3)

water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

0.004 0.006 0.008 0.010 0.012 0.014

7

8

9

10

11

12

13

14

15

visc

osity

(10

-4 N s

m-2 )

Molar concentration of LDS x ( mol dm-3)

water+LDS water+5% MT+ LDS water+10% MT+ LDS water+15% MT + LDS water+20% MT + LDS

0.004 0.006 0.008 0.010 0.012 0.014

7

8

9

10

11

12

13

14

15

16

17

18

19

Visc

osity

(

10-4

N s

m-2)

Molar concentration of LDS X (mol dm-3)

water+ LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

pressure increases for further increasing of concentration of lithium dodecyl

sulphate in aqueous and aqueous – alcoholic mixtures.

CONCLUSION

In the present study, the ultrasonic Velocity, Density, Viscosity and Internal

pressure increases whereas Adiabatic Compressibility, Free length and Free Volume

decreases with increasing concentration of lithium dodecyl sulphate in aqueous

and aqueous – alcoholic (ME & ET) mixtures. Ultrasonic velocity of Ethanol is

slightly higher than Methanol for all aqueous and aqueous – alcoholic mixtures

because of due to their chain length difference.

The CMC values are obtained in aqueous and aqueous – alcoholic (ME & ET)

mixtures of various compositions of concentration of lithium dodecyl sulphate

solutions. The higher CMC values in aqueous – Ethanol mixtures for various

composition compared to aqueous – Methanol mixtures of various composition of

concentration of lithium dodecyl sulphate . This is due to the average dielectric

constant modification in aqueous – alcoholic (ME & ET) mixtures of lithium

dodecyl sulphate solutions.

Figure-1

Figure-3

Figure-2

Figure-4

37

0.004 0.006 0.008 0.010 0.012 0.0141.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

1.55

1.60

1.65

1.70

Inte

rnal

pre

ssur

e

( 1

08 pas

cal)

Molar concentration of LDS X (mol dm-3)

water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+ LDS water+20% MT+LDS

0.004 0.006 0.008 0.010 0.012 0.0141.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

Inte

rnal

pre

ssur

e i

(108 p

asca

l)

Molar concentration of LDS X (mol dm-3)

0.004 0.006 0.008 0.010 0.012 0.0143.4

3.6

3.8

4.0

4.2

4.4

4.6

Adi

abat

ic c

ompr

essi

bilit

y

(1

0-10 N

-1 m

-2)

Molar concentration of LDS X (mol dm-3)

water+ LDS water+5% MT +LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS

Figure-5

0.004 0.006 0.008 0.010 0.012 0.0143.70

3.75

3.80

3.85

3.90

3.95

4.00

4.05

4.10

4.15

4.20

4.25

4.30

Free

leng

th L

f ( 1

0-11 m

)

Molar concentration of LDS X ( mol dm-3)

water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS

Figure-7

0.004 0.006 0.008 0.010 0.012 0.014

0.550.600.650.700.750.800.850.900.951.001.051.101.151.201.251.301.35

Free

vol

ume

Vf

(10-6

m3 )

Molar concentration of LDS X (mol dm-3)

water+LDS water+5% MT+LDS water+10% MT+LDS water+15% MT+LDS water+20% MT+LDS

Figure-9

0.004 0.006 0.008 0.010 0.012 0.014

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

Adi

yaba

tic c

ompr

essa

bilit

y

s ( 10

-10 N

-1 m

-2)

Molar concentration of LDS X (mol dm-3)

water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

Figure-11

0.004 0.006 0.008 0.010 0.012 0.0143.4

3.5

3.6

3.7

3.8

3.9

4.0

4.1

4.2

4.3

Fre

e le

ngth

(Lf)

x10-1

0 m

Molar concentration of LDS (X) mol dm-3

water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

Figure-6

0.004 0.006 0.008 0.010 0.012 0.014

0.4

0.6

0.8

1.0

1.2

Fre

e vo

lum

e (V

f) 10-6

m3

Molar concentration of LDS (X) mol dm-3

water+LDS water+5% ET+LDS water+10% ET+LDS water+15% ET+LDS water+20% ET+LDS

Figure-8

Figure-10

Figure-11

Figure-12

38

. References

1) M.S. Santosh, D. Krishna Bhat *, Aarti S. Bhatt, J. Chem.

Thermodynamics, 42, 742 (2010)

2) Ryszard Zieli´nski, Journal of Colloid and Interface Science, 235, 201

(2001)

3) Muhammad Sarwar Hossain , Tapan Kumar Biswas a, Dulal Chandra

Kabiraz , Md. Nazrul Islam ,Muhammad Entazul Huque, J. Chem.

Thermodynamics 71 6 (2014).

4) S. Chauhan , Kundan Sharma, J. Chem. Thermodynamics 71 (2014) 205–

211

5) Chanchal Das & Dilip K Hazra Indian J. CHEM vol. 44A,1793 (2005).

6) Nikam P.S. & Mehdi Hasan, J.Chem.Eng.Data, 165, 33 (1988)

39

Growth and characterization of morpholinium perchlorate

A. Arunkumar , P. Ramasamy

Department of Physics, Agni College of Technology, Chennai – 600 130

SSN Research Center, SSN College of Engineering, Kalavakkam- 603 110,

Tamilnadu, India

Corresponding author: arunkajini@gmail.com

Abstract. Morpholinium perchlorate (MP) has been synthesized and single

crystals were successfully grown for the first time by the slow evaporation

solution growth technique at room temperature. The cell parameters of grown

crystal were confirmed by single crystal X-ray diffraction analysis and it

belongs to the noncentrosymmetric space group P212121. The grown crystals

were characterized by HRXRD and UV-Vis NIR transmission analysis. The

optical nonlinearity of MP was investigated at 532 nm using 7 ns laser pulses,

employing the open aperture Z-scan technique.

Keywords; Optical properties

INTRODUCTION

Nowadays great attention has been devoted to synthesizing new organic

materials and their single crystal crystals due to their potential applications in second

and third harmonic generation, difference frequency generation, electro-optic

modulator, THz wave generation etc.,. The organic crystal can offer a highly aligned

and stable orientation of NLO chromophores in the crystal lattice. Numerous

attempts have been made to find new organic compounds with large nonlinear

optical susceptibility. Generally organic materials contain donor and acceptor groups

positioned at either end of a suitable conjugation path. Extension of benzene

derivatives has permitted an increase in the number of π electrons as well as their

delocalization length, so as to lead to remarkable enhancement in

hyperpolarizability. The large π delocalization length has been recognized as a factor

leading to large third order nonlinearity [1].In this series efforts were made to grow

MP crystals from solution in order to study their properties. Molecular ionic simple

40

complex crystals like perchlorate with Morpholine (of ratio 1:1), shows nonlinear

optical physical properties unique to the crystal structure. In the present investigation

we report the synthesis, structure and optical properties of MP.

Synthesis and Crystal Growth

Perchloric acid and morpholine were employed for the synthesis of the title

compound MP using ethanol and water. Dissolving perchloric acid in an analar grade

morpholine results in a white crystalline precipitate. Then the precipitate is allowed

to dry. The dried salt was collected and used for the further growth of MP. The

synthesized material was purified by repeated recrystallization process. The dried

precipitate was dissolved using the same solvent. But the crystallization did not

occur in this solution as it has high viscosity and low pH value. The solubility test

can be performed to choose the solvent for crystal growth. The solubility

experiments were carried out several times at temperatures 30-45˚C in the constant

temperature bath with an interval of 5˚C for various solvents such as acetone,

methanol, ethanol and mixed solvents. MP is highly soluble in acetone solvent. The

obtained dried precipitate was dissolved using acetone and then allowed to evaporate

at room temperature to yield the crystalline powder salt of MP.

The well-defined single crystals of MP were harvested from mother solution after a

growth period of 45 days. Photograph of as grown crystal is shown in

FIGURE 1.

Characterization

The grown crystals were subjected to X-ray diffraction studies. The unit cell

parameters and the crystal structure were determined from single crystal X-ray

diffraction studies. The structure was partially resolved in centrosymmetric space

group Pnma with half anions and cations in the asymmetric form and with high R –

value. But the systematic absent reflections show the absence of Pnma symmetry.

Hence the structure is refined finally in P212121 space group. The present unit cell is

indexed to a standard setting of a = 8.2802(4) Å, b = 9.7730(6) Å, c =

9.5591(5) Å and V = 773.55(7) Å3.The crystalline perfection of the grown crystals

was characterized by HRXRD and rocking curve is show in FIGURE 2. The angular

separation between the two peaks gives the tilt angle α. The tilt angle for the very

low angle boundary is 13 arc sec with respect to the main crystal block. The FWHM

41

(full width at half maximum) of the main peak and the boundary are respectively 17

and 12 arc sec. The low FWHM values of main crystal and the very low angle

boundary indicate that the crystalline perfection of the specimen is quite good. The

UV-vis-NIR spectrum is studied by Perkin-Elmer Lambda35 spectrometer with a

MP single crystal of 2 mm thickness in the range of 200-1100 nm. MP crystals

present a cut off wavelength at 215 nm with 50% transmission in the visible region

and near infrared region. the absorption at 279 nm was due to the promotion of an

electron from a ‘non-bonding’ (lone-pair) n orbital to an ‘anti-bonding’ π

orbital designated as π* (n → π*) and no characteristic absorption was observed in

the entire visible region.

FIGURE 1. Photograph of as grown

MP crystal.

FIGURE 2. Rocking curve of MP

Z-scan Measurements

An intense laser beam of 532 nm and 7 ns pulse width is split by means of a

beam splitter, and a fraction of the beam is sent to a reference photo detector where

the beam under-fills the active area of the diode. The remainder of the beam sent

through a “thin” sample is translated through the beam waist using a motorized

translation stage, after that an aperture (iris) clips roughly half of the beam intensity.

After the aperture, an open photo detector detects the remainder of the beam passing

through the iris [2]. The output of both photodiodes is sent to a dual channel energy

ratio meter interfaced to a PC.

The open-aperture Z-scan curve obtained for MP is shown in FIGURE 3. As

the sample is translated through the focal region of the beam, the open detector

measures the total transmitted intensity while the irradiance at the sample is

changing as the sample is translated, any deviation in the total transmitted intensity

must be due to multi-photon absorption. In the limit multi-photon effects are limited

42

to two-photon absorption [3]. The value of the effective two-photon absorption

coefficient is calculated using best - fit curve for the Z- scan data and is found to be

25.02 mm/GW.

FIGURE 3. Open aperture Z-scan

The estimated third order susceptibility (χ(3)) values of MP crystal is 7.185 x10-9

(esu).

Table 1. Calculated Nonlinear absorption coefficient

Conclusion

MP has been synthesized and single crystals were grown by slow evaporation

solution growth method. The cut off wavelength is 215 nm. The two photon

absorption coefficient and third order nonlinear optical susceptibility were calculated

by Z-scan technique which affirms that MP exhibits the nonlinear optical properties.

References

1. J. J. Wolff, F. Siegler, R. Matschiner, R.Wortmann,

Angew. Chem., Int. Ed. 39 (2000) 1436-1439.

2. M.Sheik-Bahae, P. Mukherjee, H.S. Kwok , J. Opt.

Soc. Am. B. 3, (1986) 379-385

3. Mikhail S. Grigoriev, Konstantin E. German and Alesia

Ya. Maruk, Acta Cryst. E64, (2008) – 390.

Input

Laser

Power

Density

(MW/mm2)

Leff

(mm)

'q'

value

from

fit

"β"

(mm/GW)

60.47 0.866 1.3103 25.02

43

Growth, Structural, spectroscopic, thermal and hardness studies of

Cesium Sulfamate single crystal

S.Rafi Ahamed1* and P.Srinivasan2

1Department of Physics, Krishnasamy College of Engineering and Technology,

Cuddalore – 607109, India

2 Department of Physics, University College of Engineering, Panruti – 607308,

India

Abstract:

Single crystals of a new semi-organic optical material of Cesium Sulfamate (CS)

have been grown by slow evaporation technique. The grown crystals were subjected

to single crystal X-ray Diffraction analysis for determining its lattice cell parameters

and its structure. The vibrational frequencies of various functional groups in the

grown crystals have been derived by FTIR analysis. The thermal studies were

performed to know the thermal behaviour. The mechanical behaviour of the grown

crystals was studied using Vicker’s Microhardness tester.

Key words: Crystal growth, Single crystal XRD, Powder XRD, Thermal Analysis,

FTIR, UV, Microhardness.

1. Introduction:

The crystals of a ANH2SO3-type consist of monovalent cations (A+ = Li+ , Na+ , K+ ,

Rb+ , Cs+ , Ag+ , NH4 + , C(NH2)3 + or (CH3)3NCH2COOH+ ) and sulfamate anions

[NH2SO3] - [1-15]. The crystal systems, space groups, lattice parameters, and elastic

constants of these crystals at room temperature have been listed in the paper as

reported by Haussühl and Haussühl [1]. It is confirmed from these data that three

crystals containing larger cations, such as A+ =Cs+ , C(NH2)3 + ,

(CH3)3NCH2COOH+ , are of monoclinic system, and other crystals are of

orthorhombic system. The melting points and fusion enthalpies for the crystals

containing the cations (A+ =Na+ , K+ , Rb+ , Cs+ , Tl+ , NH4 + ) have been

reported by Budurov and Tzolova [2]. Moreover, it has been found that KNH2SO3

and NaNH2SO3 crystals undergo phase transitions at 437.9 K with a transition

enthalpy ΔH of 4.9 kJ/mol and at 456.0 K with ΔH of 1.9 kJ/mol, respectively [3].

44

Recently, it has been reported by the measurements of DSC and elastic constants that

the KNH2SO3 crystal also undergoes another phase transition at 350 K [4].

In the recent period, search for new Non Linear Optical (NLO) materials has

escalated because of their applications like Second Harmonic Generation (SHG),

frequency mixing, electro optic modulation, optical parametric oscillation, etc.

[1].Nonlinear Optical (NLO) materials are attracting a great deal of attention due to

their applications in optical devices, such as optical switches, optical modulators,

optical communications, optical data storage and etc [2-3].

In search of new frequency conversion materials, recent interest focussed in semi-

organic materials due to their large nonlinearity, high resistance, too large induced

damage, low angular sensitivity and good mechanical hardness [4-5]. Hitherto a

series of structure determinations of the sulfamates of type A [NH2SO3] with

monovalent cations A = H, Na, K, Rb, Ag, NH4, C(NH2)3 (guanidinium) and

(CH3)3NCH2COOH (betaine) are described in literature. From a crystallographic

point of view all Sulfamate can be divided in two main series. Species with large

cations (A = Na, Rb, C(NH2)3 and (CH3)3NCH2COOH) possess monoclinic

symmetry (SCHREUER,1999). All other compounds crystallize orthorhombically.

Most of the orthorhombic sulfamates have centrosymmetric structures [6-7]. This

paper defines the crystal structure of Cs[NH2SO3]. This has been investigated by the

FTIR studies, its crystalline nature is studied by the single crystal XRD and powder

XRD. Thermal stability of the sample was tested using differential scanning

calorimetry and thermo gravimetry analysis respectively. The mechanical behavior

of the grown crystals was studied using Vicker’s Microhardness tester.

2. Experimental Procedure

2.1 Synthesis of material

Cs[NH2SO3] was synthesized by reaction of stoichiometric portions of sulfamic acid

H[NH2SO3], dissolved in deionised water, and Cesium carbonate. Single crystals of

optical quality were grown from aqueous solution by controlled evaporation over a

period of months. The reaction shown below

2 H [ NH2SO3] + Cs2CO3 2 Cs [ NH2SO3] + H2CO3

45

Good quality single crystals with well defined morphology were extracted. The

extracted single crystals of Cesium Sulfamate are presented in figure 2.

Fig.1: Grown crystals by slow evaporation method

2.2. Characterization Technique

The harvested single crystal has been analyzed by different instrumentation methods

in order to check its suitability for device fabrication. The unit cell dimensions and

space group of cesium sulfamte were obtained using a single crystal X-ray

diffractometer. Lattice parameters were calculated from 258 reflections. And also the

Powder X-ray diffraction analysis has been carried out for the as grown specimen of

Cesium Sulfamate . The presence of functional groups was identified from the

Fourier transform infra-red (FT-IR) spectral analysis. Thermal stability of the

sample was tested using differential scanning calorimetry and thermo gravimetry

analysis respectively. The mechanical behavior of the grown crystals was studied

using Vicker’s Microhardness tester.[8]

3. Result and Discussion:

3.1 Structural Determination:

The main structural features of Cesium Sulfamate are discrete [NH2SO3] - anions

linked by tetrahedral coordinated Cs+

cations (Fig.2).

Fig. 2: Projection parallel to the b r axis

illustrating the linking of the [LiO4]

46

tetrahedra chain via sulfamate groups [NH2SO3] and a system of hydrogen bonds in

Cs[NH2SO3]

The Lattice structure of Cesium Sulfamate is shown below:

Fig.3: Surrounding of Cesium with two neighbouring 6-fold rings and atomic

numbering scheme. All atoms are shown as 50% ellipsoids.

The Sulfamate groups are linked via Cesium cations. Both symmetrically

independent Cs atoms are surrounded tetrahedrally. Both tetrahedral [Cs(1)O4] and

[Cs(2)O4] shows the slight distortion from idealized geometry. Then by connecting

the neighbouring tetrahedral chains via Sulfamate groups to form a three-

dimensional framework. A system of weak hydrogen bonds N-H….O increases the

stability of the structure. At room temperature Cs(NH2SO3) crystallizes monoclinic

with the space group of P21/c .

Fig. 4: Unit cell Crystal Structure of Cs [ NH2SO3]

3.2 FTIR Spectroscopic analysis:

The vibrational measurement was carried out at room temperature. Fourier transform

infrared spectrum was obtained from Cesium Sulfamate pellet on a Perkin Elmer

47

Spectrum FT-IR spectrometer [9]. Figure – 4 shows the IR spectra of Cesium

Sulfamate crystal in the range 450-4000cm-1.

C:\Program Files\OPUS_65\MEAS\CUDDALORE SAM 1 7 1 14.0 CUDDALORE SAM 1 7 1 14 Instrument type and / or accessory 07/01/2014

3244

.51

3050

.82

2860

.44

2384

.47

2310

.72

2111

.72

1989

.77

1678

.40

1637

.48

1607

.23

1555

.92

1419

.63

1325

.55

1122

.63

1066

.06

927.

91

860.

20

100015002000250030003500Wavenumber cm-1

8688

9092

9496

9810

0

Tran

smitt

ance

[%]

Page 1/1 Fig-5: shows the IR spectrum for Cesium sulfamate

Assignments were made on the basis of relative intensities, magnitudes of the

frequencies and from the literature data. The wave numbers 1122.63 Cm-1, 1066.06

Cm-1 region are assigned on NH2 stretching. It confirms the presence of amine

group. The presence of sulfonyl group is confirm from the peak values 1678.40

Cm-1, 1637.46 Cm-1 , 1607.23 Cm-1 and 1555.92 Cm-1 regions. Also, there is no any

observation at the range of 3500 Cm-1, it shows the absence of –OH group. Thus,

the disappearance of –OH peak indicate the formation of Cesuim Sulfamate. The

observed wave numbers and the proposed assignments are listed in Table 1.

Table: 1, Wave number of absorption peaks in FTIR spectrum and their assignments

of Cs [ NH2SO3]

FTIR Cm-1 Mode Assignments

1122.63

1066.06 NH2 stretching

1678.40

1637.46

1607.23

1555.92

S-O, S=O stretching

sulfonyl group

3500 No peaks found

48

3.3. X-ray diffraction analysis:

3.3.1 Single Crystal Diffraction studies:

The Unit cell Parameters of the Cesium Sulfamate crystal are measured from a single

crystal diffractometer. The crystal parameters, Cell volume, system and space group

found to be in well agreement with that of reported values (Scheruer in 1992). The

crystal data of cesium sulfamate is presented in table.2 below.

Table 2: crystal data for Cs(NH2SO3) crystal:

Cesium Sulfamate

Molecular

Formula Determined from single

crystal XRD in present

studies

From Literature

(Phase transitions in Cesium

Sulfamate - Schreuer in

1992)

a= 8.20 A° a= 8.250 A°

b = 7.63 A° b = 7.6246 A°

c = 8.41 A° c = 8.400 A°

α = 90.00° α = 90.00°

β = 116.04° β = 116.11°

Unit Cell

Parameters

γ = 90.00° γ = 90.00°

Cell Volume Volume = 473 A3 Volume = 474.50 A3

System Monoclinic Monoclinic

Space group P 2 1/C P 2 1/C

3.3.2. Powder XRD Analysis:

The powder form of CS specimen was subjected to PXRD analysis and the recorded

spectrum using Diffraction system XPERT-PRO is depicted in fig.6.[10-11]. The

bragg’s diffraction peaks were indexed and observed prominent peaks confirm the

crystalline nature properties of grown CS crystal

49

Fig:6 shows the Powder XRD for Cesium Sulfamate( JCPS card no: 163835)

3.4. Thermal Analysis:

The thermal stability of Cesium Sulfamate crystals has been recorded using a using a

simulataneous thermal analyzer Q600 SDT and Q20 and DSC instruments. The

amount of the sample for this measurement is 12.4390 mg. The heating rates for the

DSC and TG-DTA measurements were 10 and 20 K/min with flowing dry N2 gas at

40 and 200 ml/min, respectively [12].

Figure.7: shows the DSC and TG-DTA measurements

The TG/DTA and DSC curves of Cs [ NH2SO3] crystal are illustrated in figure. From

the DTA curve, it shows that the melting point of the material takes place in the

50

surrounding area (vicinity) of 227.900C, which indicates there is no phase transition

before this temperature. The sharpness of this endothermic peak shows the high

degree of crystalline and purity of the sample.

0 100 200 300 400 500 600 700 800 900-5

-4

-3

-2

-1

0

Tem

pera

ture

Differ

ence

(0 C)

Temperature(0C)

B

Figure.8. TG/DTA behavior of CS

TG measures the amount and the rate of weight (%) change of a material with

respect to temperature. The TG studies reveals that Cs [ NH2SO3] had gradual

weight loss between 410.02°C up to near 5000C due to the liberation of CO2 and

H2O .The total decomposition of the compound is observed above 800oC. Further it

indicates there is no weight loss below 410.02°C, which shows the material can be

exploited for NLO applications.

0 100 200 300 400 500 600 700 800 900

75

80

85

90

95

100

weigh

t los

s

Temperture

B

Figure.9. TGA studies of CS

In DSC curve, there is a broad exothermic peak at 227.900C to 410.020C, which

corresponds to the decomposition as observed in TG analysis

51

0 100 200 300 400 500 600 700 800 900-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

Hea

t Flo

w

Temperature

B

Figure.10. TG/DSC Curve for Cesium Sulfamate crystal

3.5. Hardness studies:

Vicker’s test

Vicker’s test is said to be a more reliable method of hardness measurement. In order

to get a similar geometrical impression under varying loads, Smith and Sandland

(1923) have suggested that a pyramid be substituted for a ball. The Vickers hardness

test method consists of indenting the test material with a diamond indenter, in the

form of a right pyramid with a square base and an angle of 136° between opposite

faces and subjected to a load of 1 to 100 kg (Figure 8). The base of the Vickers

pyramid is a square and the depth of indentation corresponds to 1/7th of the

indentation diagonal. The longitudinal and transverse diagonals will be in the ratio of

7:1. The full load was normally applied for 10 to 15 s. The two diagonals of the

indentation left in the surface of the material after the removal of the load were

measured using a microscope, and their average was calculated. The area of the

sloping surface of the indentation was calculated. The Vicker’s hardness is the

quotient obtained by dividing the kg load by the square mm area of indentation.[13]

52

Where, HV = Vickers hardness number, P = load in kg, d = arithmetic mean of the

two diagonals. When the mean diagonal of the indentation has been determined, the

Vicker’s hardness number can be calculated from the above formula. Several

different loading settings give practically identical hardness numbers on uniform

material, which is much better than the arbitrary changing of scale with the other

hardness testing methods. The advantages of the Vicker’s hardness test are that

extremely accurate readings can be taken, and just one type of indenter is used for all

types of metals and surface treatments.

Figure-11. Shows the vicker’s Hardness test

Microhardness measurement:

Microhardness studies have been carried out in Cesium Sulfamate single crystals

using HMV Shimadzu microhardness tester filled with diamond Vickers pyramidal

indenter to estimate the mechanical properties. Crystals with flat and smoothness

surfaces were taken for the static indentation test and the same crystal was mounted

on the base of the microscope. The indentations were made gently by varying the

loads from 5 to 25g for a dwell period of 15s using the vicker’s diamond pyramid

indenter attached to an incident ray research microscope. The intended impression of

53

5 10 15 20 2520

30

40

50

60

70

80

90

Hv(

Kg/

mm

2 )

Load(P) Kg

B

vicker’s was approximately square in shape. The shape of the impression is

dependent on the structure, face and materials used.

After unloading, the length of the diagonals was measured by a calibrated

micrometer attached to the eyepiece of the microscope. For each load, at least five

well defined indentations were considered and the average was taken as d. The

elastic stiffness constant (C11) was calculated using Wooster’s empirical relation as

(Wooster, 1953).

The vicker’s hardness was calculated using the standard formula and the values are

tabulated below.

Load (P) Kg Hv (Kg/mm2) C11 x 1014 Pa

5 85.4 23.99

10 67.9 16.06

15 48.8 9.01

20 33.5 4.66

25 25.5 2.89

The values of C11 give the idea of toughness of bonding between neighboring atoms.

Here, the high values of C11 indicates the strong binding forces between the ions,

While the small values of C11 indicates the binding force between the ions are not

quit strong. Thus, the decrease of microhardness with load is in good agreement with

the normal indentation size effect (ISE).[14].

Fig.12 Hardness behavior of Cesium Sulfamate

54

Conclusion:

A high quality semi-organic optical transparent crystal of Cesium sulfamate was

synthesized by slow evaporation solution growth method at a room temperature

using deionised water as a solvent.

1. The crystal parameters, Cell volume, system and space group found to be in

well agreement with that of reported values. At room temperature

Cs(NH2SO3) crystallizes monoclinic with the space group of P21/c .

2. From the Powder X-ray measures, the Bragg’s diffraction peaks were indexed

and observed prominent peaks confirm the crystalline nature properties of

grown CS crystal. The powder XRD confirmed the structure of the crystal

compound.

3. The vibrational frequiencies were assigned from FT-IR spectral analysis,

which confirm the presence of functional groups of the cesium sulfamate

material.

4. The thermal studies confirm that the crystal structure is stable up to 410.020C

and indicate its suitability for use in various applications.

5. The micro hardness study confirms the mechanical strength of the layers of

the sample. Thus, the decrease of microhardness with load is in good

agreement with the normal indentation size effect (ISE).

Reference:

[1] D.S. Chemla and J. Zyss, Academic Press, London (1987).

[2] Marcy H.G,Waarren L.F,Webb M.S,Ebbrs C.A,Velslo S.P,Kennedy G.C, and

Catela G.C,Appl.Opt, 31(1992)5052.

[3] Hou W.B,Jang M.H,Yuan D.R,Xu D,Zhang N,Liu M.G and Tau

mater.Res.bul(1993) 28,645.

[4] Xing G,Jiang M, Zishao X and Xu D J. Lasers 14(1987) 357

[5] Versko S,Laser Program Annual Report, Lawrence UCRC-JC 105000,Lawrence

Livermore National Laboratory Livermore, CA. (1990).

[6] Warren L.F, Electronic Materials our future in: Allred R.E, Martinez R.J,

Wischmann K.B, (Eds), Proceedings of the Foruth International Sample Electronics

55

Society for the Advancement of Materials and Process Engineering Of Materials and

Process Engineering, Covina, (1990)CA,Vol.4 .p. 388.

[7] Landott Bornstein In: K.H.Hettwege, A.M.Hellwege (Eds) ,Numerical Date And

Functional Relationship In Science And Technology,(1982)Group, 14, Springer,

Berlin.p.584.

[8] Sagadevan Suresh, Techniques and tools used for investigating the grown

crystals: A review, (2012).

[9] R. Mohan Kumar, D. Rajan Babu, D.Jayaraman.,R Jayavel and K.Kitamur,

J.Crystal Growth, 275, 1935 (2005).

[10] S. Selvakumar, S.M. Ravi Kumar, Ginson P. Joseph, K. Rajarajan, J.

Madhavan, S.A. Rajasekar, P. Sagayaraj, Materials Chemistry and Physics, (2007)

Vol 103, Issue 1, pp 153-157.

[11] M. Iyanar, J.Thomas Joseph Prakash and S.Ponnusamy, Journal of Physical

sciences, Vol.13,2009,235-244.

[12] J.Chandrasekaran, P.Ilayabarathi and P.Maadeswaran, Rasayan J.Chem, Vol.4,

No.2 (2011), 425-430.

[13] Suresh Sagadevan and R.Varatharajan, international journal of physical

sciences,Vol. 8 (39),PP. 1892-1897, 23 october,2013.

[14] R.Hanumantharao and S.Kalainathan, Bull. Mater. Sci., Vol.36, No.3,June

2013,PP. 471-474, @ Indian Academy of Science.

56

INTRAMOLECULAR WEAK HYDROGEN BONDS IN SOME SIX AND

FIVE ATOM INTERACTIONS: SPECTROSCOPIC ANALYSIS

D.Nandha kumara, Dr.V.Periyanayagasamib

aDepartment of Chemistry, St.joseph’s college of arts and science,

Cuddalore – 607001. bDepartment of Chemistry, St.joseph’s college of arts and science,

Cuddalore – 607001.

Abstract:

CH---X (X = N and O) hydrogen bonds formed intramolecularly in 2-methyl-

4-(2,4,5-trimethoxyphenyl) thiazole (Ia), and 2- amino - 4 - (2,4,5-

trimethoxyphenyl) thiazole (Ib) were studied by means of all-electron calculations

performed with the B3LYP/6-311++G (d,p) method. Computed ground states, in the

gas phase, show the presence of a single H-bond and two H-bonds, CH---N and CH-

--O, for each Ia and Ib molecule. H---N, and H---O distances are shorter than the

sum of the X and H van der Waals radii. H-bond energies of =4.0 kcal/mol were

estimated for Ia and Ib. These results agree with those of the theory of DFT/B3LYP

level, the chemical shifts in the 1H NMR were calculated by the GIAO method; in Ia

and Ib they are merely due to the different topological positions of the H atoms. in

Ia and Ib the shifts of H---N and H---O have signatures of H-bond formations. A

study on the electronic and optical properties (absorption wavelengths, excitation

energy, dipole moment and frontier molecular orbital energies) is performed using

DFT methods. Stability of the molecule arising from hyper conjugative interactions,

charge delocalization has been analysed using natural bond orbital (NBO) analysis.

The calculated HOMO and LUMO energies gap are displayed in the figures, which

show the occurrence of charge transformation within the molecule. NLO properties

related to polarizability and hyperpolarizability are also discussed.

Keywords: Intramolecular hydrogen bonding, Thiazole derivatives, Atomic-ring

interactions, Physical Chemistry, gauge-independent atomic orbital; chemical

shifts;G09 and Veda.

57

Introduction

Thiazole is an important heterocyclic molecule which is strongly

hydrogen bonded in the solid state. and it is a small five membered ring for which

the vibrational spectra have not yet been fully studied computationally[1] Thiazole

and its derivatives have received a great deal of attention and they have versatile

chemistry and constitute reactive moieties of several biochemical systems as well as

ligands of many organometallic compounds[2] There have been several studies

reported for the vibrational analysis of thiazole derivatives in the most of these

studies only the IR spectra with particular emphasis on the N-H and C-H stretching

regions it is anticipated that DFT level of theoretical calculation with two different

basis set are reliable for predicting the vibrational and NMR spectra of 2-methyl-4-

(2,4,5-trimethoxyphenyl)thiazole(Ia).The2-amino-4(2,4,5trimethoxyphenyl)thiazo le

(Ib) has been the object of many spectral, structural and theoretical investigations

because of its interesting chemical and physical properties however the crystal study

of candidate molecule is not available in the literature.

The molecules taken for study are 2-methyl-4-(2,4,5-

trimethoxyphenyl)thiazole and it derivatives. The molecular formula of base

compound is C13H15NO3S and the molecular weight is 265.328g/mol. It is a kind of

beige crystalline powder. Thiazole and phenyl rings in the title molecule with

methoxy substituent is prone to form intramolecular hydrogen bonding, that is

favored both by the free rotation around the C-C bond, joining the thiazole and

phenyl rings and by the kind of hetero atoms or functional groups attached to the

rings. The physicochemical properties of these thiazole derivatives may depend on

the type of H-bonds that these compounds can form. In fact the use of 1H NMR and

X-ray diffraction methods[2,3]. The hydrogen bonding energies were calculated by

rotating about the C-C bond between the rings, breaking the H-bonds, frequency

calculations were done to ensure the structures are minima[7].CH-----X (X= N and O)

hydrogen bonds formed intra molecularly in Ia and Ib. have been studied by means

of all-elecrton calculations performed on B3LYP/6-311++G(d,p) level of theory for

ground state.

58

2.Computational methods

In the present work, DFT hybrid method such as B3LYP/6-311++G(d,

p) method was used to carry out full optimization, which includes relaxation of

geometry and electronic structure of two polysubstituted arylthiazoles derivatives 2-

methyl-4-(2,4,5-trimethoxyphenyl)thiazole (Ia) and 2-amino-4-(2,4,5-

trimethoxyphenyl)thiazole (Ib) was carried out with the B3LYP/6-311++G(d, p)

method. The B3LYP functional has been widely used for the study of weak

hydrogen bonds. All-electron calculations were performed with the aid of the

Gaussian 09 program package on an i7 processor in a personal computer. In DFT

methods, B3LYP is the combination of Beckes three-parameter hybrid function, and

the Lee-Yang-Parr correlation function. The optimized molecular structure of the

molecule obtained using the Gaussian 09 and Gaussview program and is shown in

Fig.1. The observed (FT-IR) and calculated vibrational frequencies and vibrational

assigments are shown in Table 2. Geometric, energetic, topological, and

spectroscopic (chemical shifts) parameters were used for the characterization of

these H-bonds. A vibrational analyses for all molecules were carried out , finding

that the optimized geometries correspond to a minimum on the potential energy

surface, by confirming no imaginary frequencies. Stability of the molecule arising

from hyperconjugative interactions, charge delocalization is analyzed using natural

bond orbital (NBO) analysis. The electronic properties, HOMO-LUMO energies,

Moreover, dipole moment, polarizability, hyper polarizability related to nonlinear

optical (NLO) properties were also studied. The chemical shifts were calculated for

these optimised structures by means of the gauge invariant atomic orbital (GIAO

method).

Results and discussion

3.1. Molecular geometry

In computational study the geometry optimization is the foremost important

step to identify the ground state geometry of candidate molecule. In present study

the geometry of the title molecule has been optimized for B3LYP method with 6-

311G(d,p) basis set along with frequency calculation. Geometry with no imaginary

frequency corresponds to local minima. The optimized geometric parameters of 2-

methyl-4-(2,4,5-trimethoxyphenyl) thiazole derivatives-Ia and 2-amino-4-(2,4,5-

59

trimethoxyphenyl) thiazole derivatives-Ib calculated at DFT theory level [17-19]are

listed in table (1) and they are in accordance with the atomic number scheme given

in Fig (1)

Ia-BondlengthÅ Ib-BondlengthÅ

Figure 1. Optimized B3LYP/6-311++G(d,p) Bond length for the bare Ia-Ib

derivatives. The CH---N, and CH---O distances, in Å, are indicated as well as the

dihedral angles, C5C6C12C13, in deg

Ia-Bond angle Å Ib-Bond angle Å

Figure 2. Optimized B3LYP/6-311++G(d,p) Bond angle for the bare Ia-Ib

derivatives. The CH---N, and CH---O distances, in Å, are indicated as well as the

dihedral angles, C5C6C12C13, in deg

3.2. VIBRATIONAL ANALYSIS

The title molecules are quasi planar with C1 symmetry and there are 33

atoms and 32 atoms in Ia and Ib, respectively there correspond 93 and 92

fundamental vibrations, in fact all are both IR and Raman active. The vibrational

frequencies are further identified interms of PED study using VEDA software. For

60

Thiazole Derivatives The various mode of vibrations computed at DFT/B3LYP6-

311++G(d,p) level have been assigned.

C-H Stretching vibration

The aromatic C-H stretching vibration are normally found in the region

between 3100-2950 cm-1[9-12]. According to the present the aromatic C-H Stretching

vibrations are assigned in the region 3264-3260 cm-1/DFT –B3LYP/6-31G (d,p)

method.

C-C Stretching

The C-C thiazole stretching vibrations give rise to characteristic bands in both

the IR and Raman spectra covering the spectral range from 1600-1400 cm-1[13]

assigned in the region 1664, 1636, 1579 cm-1 DFT/B3LYP-6-31G method. The

phenyl ring C-C Stretching vibration are assigned in the region are 1664, 1636,

1613, 1579, 1558, 1418 cm-1 /DFT/B3LYP6-31G method. This is in good agreement

with literature value[13]

C-N Stretching

The C-N stretching frequency is a rather difficult task since there are problem

in identifying these frequencies from the other vibrations.Silverstein[14-15] assigned

C-N Stretching absorption in the region 1386-1266 cm-1 computed C-N Stretching

vibrations are assigned at 1636, 1299, cm-1 /DFT /B3LYP6-31G method

C-O Stretching

The medium intensity band observed at 1075 cm-1[17] in the IR spectrum could

be assigned to the title molecule has three C-O band their corresponding vibration

are assigned in 1331, 1221, 1182, 1240, 1037 cm-1/DFT /B3LYP6-31G method.

C-H-O-H Out plane Bending vibration

The computed C-H-O-H Out plane Bending vibration are assigned in the

region 1523, 1531, 1506, 1532 cm-1 respectively DFT/B3LYP6-31G method.[14,16]

61

H-C-C-O and H-C-C-N torsional vibration

The computed H-C-C-O and H-C-C-N torsional vibration and C-C-C-S

vibration are assigned in the region 893, 951, 832 and 76, 1522,1088 cm-1

respectively DFT/B3LYP6-31G method.[15]

3.3 Thermodynamic Property

Thermodynamics is the one of the well-developed mathematical descriptions

of chemistry. Computational results can be related to thermodynamics. The results of

computations might be internal energies, free energies and so on, depending on the

computation performed upon the molecule. Likewise, it is possible to compute

various contributions to the entropy[23-25]. Thermodynamic quantities of the title

compound are present in table (5)

Table .5 Theoretical computed energies, zero-point vibrational energies

(kcal/mol), rotational constants, entropies (JK-1) and dipole moment (Debye) for

Thiazole derivatives.

Parameter DFT/B3LYP6-31G

Total energy 175.128

Zero-point energy 684056.9(J/mol)

Rotational constant 0.5954

0.2298

0.1682

Entropy

Total Kcal/mol

Translational 0.889

Rotational 0.889

Vibrational 173.350

62

3.4. NMR STUDY

Theoretical study of the chemical shifts in the 1H NMR was carried outs by

the GIAO method at the B3LYP/6-311++G(d,p) electronic level of treatment[30-36].

This approach also may be useful for a potential identification of H-bonds. The

Calculated chemical shifts, in ppm for some representative hydrogen atoms of the Ia-

Ib Species are shown in Table 10.

Table 10. calculated GIAO B3LYP/6-311++G(d,p) Chemical shifts, in ppm, for

the Benzene H8 and H28 atoms involved in the H-Bond interactions and for the

Aromatic H8 atoms not forming H-Bonds

Molecule H8 H28 H7

Ia 8.49(7.90) 8.23(7.74) 7.54(6.63)

Ib 8.49(7.63) 8.23(7.08) 7.54(6.57)

Some anomalous behavior have been observed for protons of Ia and Ib, specifically,

H8 and H28 which seem to be at the bridging site of phenyl and thiazole rings

moreover they are oriented towards the oxygen of methoxy groups, naturally

susceptible to establish intramolecular H-bonding. This is quite evident from the

large value significantly larger, by 1.42-1.89 ppm, than that of the H7 perhaps, a

signature of blue shift H-bonding. The magnitude of these shifts is in agreement with

the estimated higher H-bond energy, 4.1 kcal/mol for Ia and Ib, which show the

formation of two, C16H28--O29 and C5-H12—N17, H-bonds.[30,32-35]

Conclusion

The non conventional CH---X (X= N, O) H-bonds formed intramolecularly in the

Ia-Ib thiazole derivatives were studied at B3LYP/6-311++G(d,p) level interms of

geometrical and spectroscopic properties to characterize the H-bond centres. The

computed properties for the ground state suggest the formation of an H-bond

between C16H28-O29, in both Ia and Ib which is quite evident from the geometrical

criteria where the H---O distance is found to be 2.241 Å, in both Ia and Ib, however,

63

it is obvious that there is no interaction between C1H7 and N18 which is quite

evident from the bond length H8---N18 2.34-2.35. The chemical shifts in the 1H

NMR were also calculated by the GIAO method to further confirm the blue shift H-

bond signatures from chemical shift values.

REFERENCES

(1) Joule, J. A.; Mills, K. 1,3-Azoles: imidazoles, thiazoles, and oxazoles: reactions and synthesis. In Heterocycle chemistry,4th ed.; Blackwell Sciences Publishing: Oxford, U.K., 2002;pp 402-425. (2) Sa´nchez-Viesca, F.; Berros, M. Heterocycles 2002, 57,1869-1879. (3) Berne´s, S.; Berros, M. I.; Rodrı´guez de Barbarı´n, C.;Sa´nchez-Viesca, F. Acta Crystallogr., Sect. C: Cryst. Struct.Commun. 2002, C58, o151-o153. (4) Castellano, R. K.; Diederich, E. A.; Meyer, E. A. Angew.Chem., Int. Ed. Engl. 2003, 42, 1210-1250. (5) Desiraju, G. R. Acc. Chem. Res. 2002, 35, 565-573. (6) Dincüer, M.; O¬ zdemir, N.; Cü ukurovali, A.; Yilmaz, I. ActaCrystallogr., Sect. C: Cryst. Struct. Commun. 2005, E61,o1712-o1714. (7) Desiraju, G. R.; Steiner The Hydrogen Bond. In The weak hydrogen bond in structural chemistry and biology, 1st ed.; Oxford University Press, Inc.: New York, 1999; pp 1-28. (8) Grabowski, S. J.; Pfitzner, A.; Zabel, M.; Dubis, A. T.;Palusiak, M. J. Phys. Chem. B 2004, 108, 1831-1837. (9) G. Socrates. Infrared and Raman Characteristic Group Frequencies, Tables and Charts, third , John Wiley and Sons. Chichester, 2001 34 C.P. Dwivedi, S.N. Sharma.Indian (10) C.P. Dwivedi; S.N.Sharma; Indian J. Pure appl.Phys. 11(1973) 447 (11) G. Varsanyi. Assignments for Vibrational Spectra of Seven Hundred Benzene Derivatives, 1-2, Addam Hilger, 1974 (12) N.P.Singh; R. A.Yadaw .Indian J.Phys. B75 (2001) 347 (13) N.P.G. Roeges, A Guide to the complete interpretation of Infrared spectra of hetero organic structure, Wiley, New York,1999. (14) M. Silverstein , G.C. Basseler, C.Morill, Spectrometric identification of Organic Compounds, Wiley, New York, 1981. (15) L.J.Bellamy , R.L. Williams, Spectrochem. Acta A9 (1957) 341. (16) N.B. Colthup, L.H.Daly, S.E. Wilberley, introduction to Inftrared and Raman Spectroscopy, Academic Press, New York, 1964. Pp. 226 (17) J.H.S. Green , D.J. Harrison, W.Kynoston, Spectrochim.Acta 27A (1971) 807. (18) ) Becke, A. D. J. Chem. Phys. 1993, 98, 5648-5652. (19) Lee, C.; Yang, W.; Parr, R. G. Phys. ReV. 1988, B37, 785-789. (20) T.Clark, A Hand book of computational Chemistry John Wiley and Sons , New York (1985)(21) A.E.Reed, R.B.Weinstock, F.Weinhold, J.Chem.Phys, 86(1945) PP.735-746.

(22) A.E.Reed, L.A.Curtiss, F.Weinhold, Chem.Rew.88(1988) PP.899

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(23) Devid C. Young, Computational Chemistry, John Wiley and Sons, New York,

1st ed.,(2001)

(24) W.Cornell, S.Louise-May.Encycl.Comput.Chem.3(1998)PP.1904.

(25) J.J.P.Stewart,Encycle. Comput.Chem.4(1998)PP.241

(26) D.A.Kleinman,Phys Rev.126(1962) PP.1977.

(27) L.J. Bellamy, The Infrared Spectra of Complex Molecules,vol.2,Chapman and

Hall,London,(1982)

(28) R.G.Parr, R.A.Donnelly,M.Levy,W.E.Palke,J.Chem.Phys.68.(1978)PP.3801.

(29) R.P.Iczkowski,J.L.Margrave,J.Am.Chem.Soc.83(1961)PP.3547.

(30) Scheiner, S; Gu, Y.; Kar, T. J. Mol. Struct. (THEOCHEM) 2000, 500, 441-452.

(31) Rozas, I.; Alkorta, I.; Elguero, J. J. Phys. Chem. A 2001, 105, 10462-10467.

(32) Scheiner, S.; Grabowski, S. J.; Kar, T. J. Phys. Chem. A 2001, 105, 10607-

10612.

(33) Mizuno, K.; Ochi, T.; Shindo, Y. J. Chem. Phys. 1998, 109, 9502-9507.

(34) Alkorta, I.; Elguero, J. New J. Chem. 1998, 381-385. CT600336R .Chem. Soc.

1995, 117, 12875-12876.

(35) Ibon Alkorta, Jose Elguero, “Non- conventional Hydrogen Bonds”, Royal

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(36) George A. Jeffrey, An Introduction to Hydrogen Bonding, Oxford University

Press, New York, USA, 1997, pp. 85, 228.

(37) Gautam R. Desiraju, Thomas Steiner, The Weak Hydrogen Bond, Oxford

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(38) AIM2000 designed by Friedrich Biegler-konig, University of Applied Sciences,

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65

Growth and Characterization of Bis Thiourea Potassium Acid Phthalate

(BTKAP) Single Crystals

N. Jhansi1, K. Mohanraj1, D. Balasubramanian*1

1Raman Research Laboratory, PG & Research Department of Physics, Government

Arts College, Tiruvannamalai-606603

Corresponding author: mohan1991mpt@gmail.com Mobile: +91 9677971999

Abstract

A new non-linear optical single crystal of Bis thiourea Potassium Acid

Pthalate (BTKAP) was grown by slow evaporation technique. The Fourier transform

Infrared Spectrum (FTIR) was recorded for the grown crystal to identify the various

functional groups present in the compound. The X-ray diffraction (XRD) technique

is reported the crystalline nature and crystal structure of the grown BTKAP. The

UV-visible spectral analysis was used to study the linear optical behavior of the

BTKAP single crystals. The second harmonic generation efficiency of the grown

crystal was measured using Kurtz- Perry technique and it is found that two times

more than KDP crystal. It indicates that grown crystal is a potential material for

NLO applications.

Keywords: BTKAP, FTIR, powder XRD, SHG, and UV-Vis.

1. Introduction

In recent trends NLO materials for second harmonic generation (SHG) have

important for an applications in the field of telecommunication, optical computing,

optical information processing, optical data storage technology, laser remote sensing,

laser driven fusion and color displays, in addition to their usual role of extending the

required frequency available from a laser [1-3]. Over the years, many organic and

inorganic materials have been developed to cover the potential applications in

ultraviolet, near and far-infrared wavelength regions [4-6].

Organic crystals with large nonlinear optical (NLO) response make them

suitable for applications in frequency conversion and optical processing [5].Organic

66

nonlinear optical (NLO) materials are often formed by weak Vander Waals and

hydrogen bonds and hence possess a high degree of delocalization. The NLO

properties of organic crystals structure are mainly due to π- bond system. The

overlap of π-orbitals causes the delocalization of electronic charge distribution,

which leads to a high mobility of electrons. This leads to more asymmetry and hence

increased optical nonlinearity.

In the present investigation, potassium acid phthalate has been added to their

in the ratio 1:2 and from the obtained product, single crystal of Bis thiourea

potassium acid phthalate (BTKAP) were grown. The grown crystal was subjected to

various characterization techniques.

2. Experimental procedure

2.1. Material Synthesis

Bis thiourea potassium acid phthalate single crystal was synthesized by using

High purity (99%) Thiourea and Merck grade Potassium Acid Phthalate were taken

in 2:1 molar ratio and dissolved in de-ionized water of resistivity 18.2 MΩ/cm and

stirred with the help of magnetic stirrer for more than four hours at a room

temperature. The prepared solution was taken to dry at room temperature. The Bis

Thiourea Potassium Acid Pthalate (BTKAP) compound was obtained. The purity of

the synthesized compound was improved by successive recrystallization process.

2.2. Seed Preparation

The synthesized BTKAP compound was dissolved in deionized water and the

solution was prepared in slightly undersaturated condition. The solution was

continuously stirred up to 8 hours using magnetic stirrer and then filtered. Then the

filtered solution was transfer to Petri dish and closed by porous paper. The seed

crystals were grown over a period of 10-20 days. Good quality large crystal was

grown from seed crystals by slow evaporation technique. One of the best seeds

obtained was tied hung in the supersaturated solution. After introducing the seed

crystal, BTKAP single crystal was grown to the considerable size as shown in the

figure 2.1

67

Figure 2.1BTKAP single crystals grown from slow evaporation technique.

3. Result and Discussion

3.1. Single crystal X-ray diffraction studies of BTKAP single crystals

BTKAP single crystals was subjected to single crystal X-ray diffraction

analysis using a ENRAF- NONIUS CAD-4 single crystal X-ray diffractometer with

Mo Kα (λ = 0.7170 Å) radiation. The lattice parameter are given in the table 1.the

XRD data of BTKAP crystallize with orthorhombic structure.

Table 1. Single crystal XRD data of TTKAP crystal

Sample Lattice Parameters

a(Å) b(Å) c(Å) V(Å3) BTKAP

6.51 9.77 13.68 90 90 90 887

3.2. Powder X-ray diffraction studies of BTKAP single crystals

The powder sample of BTKAP crystal was subjected to powder X-ray

diffraction analysis using a Rich Seifert diffractometer with CuKα (λ = 1.5418 Å)

radiation. The sample was scanned over the range 10 to 55 degrees at a scan rate of 2

degree/minute. The recorded X-ray pattern of BTKAP is shown in figure 3.2; the

figure shows a sharp and intense peak which confirms the good crystalline nature of

the grown crystal.

Figure 3.2.The powder X-ray diffraction pattern of BTKAP crystal

68

C:\Program Files\OPUS_65\MEAS\BIS.0 BIS Instrument type and / or accessory 07/12/2012

3877

.75

3730

.58

3682

.27

3587

.60

3509

.24

3376

.83

3264

.93

3172

.01

3104

.69

3068

.43

2958

.62

2794

.70

2628

.96

2487

.83

1950

.53

1672

.31

1561

.94

1481

.65

1380

.99

1284

.99

1148

.29

1089

.18

851.

1880

7.54

763.

1971

9.68

681.

1964

5.70

581.

5854

8.32

485.

8142

3.98

391.

27

500100015002000250030003500Wavenumber cm-1

020

4060

8010

0

Tran

smitt

ance

[%]

Page 1/1

3.3. FTIR Analysis

The FT-IR spectrum was recorded using BRUKER IFS-66V FT-IR

spectrometer by pellet technique by KBr pellet technique on the range 400-4000 cm-1

to confirm the presence of the various functional groups in the grown BTKAP

crystals. The infrared spectrum of BTKAP is shown in figure 3.3.

From the FTIR spectrum of the grown crystal, it is found that symmetric C=S

stretching of theory is observed at 719 cm-1. The C-C-O stretching mode occurred at

1089 cm-1. The absorption band at 1561 cm-1 is due to NH2 is group deformation.

The =CH valance and ≡CH valance of there are observed at 3172 cm-1 and 3264

cm-1. The ≡CH symmetrical band is assigned at 3376 cm-1. The peaks at 548 cm-1

shows the C=C-C out of plane ring deformation, 681 cm-1 conforms C-O wagging in

KAP and 854 cm-1 is assigned to C-H out of plane bending is KAP. The absorption

band at 1431 cm-1 and 1672 cm-1 correspond to O-H in plane bending and C≡O

Figure3.3. FTIR Spectrum of BTKAP single crystal

stretching respectively, which conform the presence of functional groups in the

grown BTKAP single crystal.

69

4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 00 .0

0 .5

1 .0

1 .5

2 .0

2 .5

3 .0

3 .5

4 .0

4 .5

Abso

rptio

n (a

.u.)

W a v e le n g th (n m )

3.4 UV- Vis studies

The BTKAP single crystal of thickness 3mm sample was placed in the

Varian Cary 5E UV-VIS-NIR spectrophotometer. The absorption spectrum was

record in the range 200 nm to 1100 nm. The recorded spectrum is shown in the

figure 3.4. The small absorption in the near UV region is due to a weak σ-π*

transitions. As there is no absorption in the entire Vis-NIR range with a lower cutoff

at 330 nm, the transmission window in the visible and IR region so the grown crystal

posses good optical transmission of the second harmonic frequencies of Nd:YAG

lasers[7].

Figure 3.4. Optical Absorption spectrum of BTKAP crystal

3.5. Nonlinear optical studies of BTKAP

The prerequisite for the nonlinear optical crystals is that they should posses

the non-centrosymmetric space group. Hence it is highly desirable to have some

technique of screening crystal structures to determine whether they are non-

centrosymmetric and it is also equally important to know whether they are capable

for phase matching to produce a second harmonic generation.

Kurtz and Perry (1968) [8] proposed a powder SHG method for

comprehensive analysis of the second order nonlinearity (Figure3.5).Kurtz and Perry

second harmonic generation (SHG) test was performed to confirm the NLO property

of BTKAP single crystal. The powdered crystalline sample was illuminated using

Spectra Physics Quanta Ray DHS-2. Need: YAG laser using the first harmonic

output of 1064 NM with pulse width of 8 NS and repetition rate of 10 Hz. KDP

sample was used as the reference material.

70

TEKTRONIX555

EMI 9524PHOTO

MULTIPLIERQ-SWITCHED

LASER1.055 µ

RCA 925PHOTOTUBE

H V SUPPLY

PRE-AMPADYU A-102E

TRIGGER

(w) 2w

CH 1

CH 2

(2w)(w)

Figure 3.5. Schematic diagram of the apparatus used for the study of

second harmonic generation in powder

The second harmonic signal generated in the crystalline sample was

confirmed by the emission of green radiation (λ = 532 nm) from the BTKAP crystal.

The green radiation of 532 nm was collected by a photomultiplier tube (PMT, Philips

Photonics—model 8563) after being monochromatic by a monochromator—model

Triax- 550. The optical signal incident on the PMT was converted into voltage

output at the CRO (Tektronix—TDS 3052B).

A second harmonic signal of 108mv was obtained, while the standard KDP

crystal gave a SHG signal of 46mv/pulse for the same input energy. Hence the SHG

efficiency of the grown crystal is found to be more than two times that of the KDP.

In the powder sample used, the small crystallites were oriented in different directions.

The efficiency of the frequency conversion will vary with the particle size and

the orientation of the crystallites in the capillary tube. Hence, higher efficiencies may

be expected to be achieved with single crystals, by optimizing the phase matching.

4. Conclusion

The Bis thiourea potassium acid phthalate was synthesized and the seed

crystals were grown from the crystallization by slow evaporation technique. The

Purity of the synthesized crystals was improved by successive recrystallization

process. The X-ray diffraction analysis confirmed the crystalline nature and

structure of the grown BTKAP single crystal. The FTIR spectrum was confirm the

presence of the various functional groups in the grown crystal. UV visible spectrum

of grown crystal as the lower cut off value 330nm; it is a potential material for NLO

71

applications. Kurtz- Perry powder technique confirmed the NLO property of the

grown BTKAP crystal and its second harmonic generation efficiency is found to be

more than 2 times that of KDP.

References

[1] Yuan D., Zhong Z., Liu M., Xu D., Qi Fang, Bing Y., Sun S. and Jiang M.

(1998), ‘Growth of cadmium mercury thiocynate single crystal for laser diode

frequency doubling’, J. Crystal Growth, Vol. 186, pp. 240-244.

[2] Anandhabahu G., Bhagavanarayana G., Ramasamy P., (2008), Journal of

crystal growth 310(2008)2820-2826.

[3] Prasad P. N., Williams D. J., (1991) Introduction to Nonlinear Optical Effects

in Molecules and Polymers, Wiley- Interscience, New York.

[4] Hann R.A. and Bloor D. (1989), ‘Organic Materials for Nonlinear Optics’, the

Royal Society of Chemistry, Special Publications No. 69.

[5] Badan J., Hierle R., Perigaud A. & Zyss J. (1993) NLO Properties of

Organic Molecules and Polymeric Materials, American Chemical Society

Symposium Series 233; American Chemical Society: Washington, DC.

[6] Chemla D.S. and Zyss J. (1987), ‘Nonlinear optical properties of organic

molecules and crystals’, Academic Press, Orlando, New York, Vol. 1-2.

[7] Kannan V., Rajesh N.P., Bairava Ganesh R., Ramasamy P. ‘Growth and

characterization of Bisthiourea- Zinc Acetate, a new nonlinear optical

materials’ , Journal of Crystal Growth 269(2004) 565-569.

[8] Kurtz S.K. and Perry T.T. (1968), ‘A Powder technique for the evaluation of

nonlinear optical materials’, J. Appl. Phys., Vol. 39, pp. 3798-38l3.

72

Growth, Structural, Thermal, and Mechanical Properties of Succinic Acid

Doped Potassium Hydrogen Phthalate (KHPSA) Crystal

R. Aruljothia, R. U. Mullaia, E. Vinotha, M. Sheik Muthalia, S. Vetrivela*

aPG & Research Department of Physics, Government Arts College, Tiruvannamalai-

606 603, India

*Corresponding author: vetrivelsivaraman@yahoo.com

Abstract

Succinic acid doped Potassium hydrogen phthalate (KHPSA) semi-organic

single crystals were grown by slow evaporation method at room temperature. Single

crystal X-ray diffraction study revealed that the KHPSA crystal belongs to

orthorhombic system. FTIR spectral analysis confirms the presented functional

groups in the synthesized compound. The UV–Vis–NIR spectrum showed that the

grown crystal is transparent in the entire visible region. The hardness profile of the

sample is investigated by Vicker’s micro hardness test. TGA/DTA analysis were

carried out to characterize the melting behavior and stability of the title compound.

Microstructure and compositions of the KHPSA crystal was carried out by SEM with

EDS.

Keywords: crystal growth, X-ray diffraction, FTIR spectral analysis, UV–Vis–NIR

spectrum, micro hardness, thermal analysis, and SEM.

1. Introduction

The search for new conversion materials for various device applications has

led to the discovery of many organic, inorganic and semi organic Non Linear Optical

(NLO) materials. Among these, Semi organic crystals have attracted considerable

interest due to their large NLO coefficients, high resistance to laser induced damage,

low angular sensitivity, excellent mechanical hardness fluorescence properties

because of their potential applications such as, telecommunication, optical

computing, optical data storage, light emitting diodes, and optical information

processing [1, 2]. Semi organic compounds exhibits dipolar structure, improved

mechanical-thermal properties, chemical stabilities and bulk crystal morphologies.

Potassium hydrogen phthalate (KHP) is also called as potassium acid

phthalate (KAP) is a semi-organic material. It is also one of the important NLO

73

crystals in the alkali metal acid phthalate (MAP) family [3]. It belongs to the

orthorhombic class of alkali acid phthalate series. The crystal structure of KAP is

assigned to the Pca21 [4] space group, consisting of potassium ions and alkali

phthalate ions. Recently KAP crystals were used as substrate for epitaxial growth of

oriented polymers [5, 6] and for hierarchical growth of organized materials [7]. KAP

crystals are playing an important role in the field of NLO materials, they are known

second harmonic generating materials that have long stability in devices due to their

electro- optical properties [8] and exhibit interesting piezoelectric, pyroelectric and

elastic properties that are useful in many application [9,10]. Its higher chemical

stability and economic viability with good kinetic growth properties have made to

pay attention on it in past decades.

Generally Succinic acid has wide applications in many fields, like industry,

medicinal, organic intermediates for the pharmaceutical, engineering plastics, resins.

Particularly in the chemical industry it is used for the production of dyes, alkyd resin,

glass fiber reinforced plastics, ion exchange resins and pesticides.

By using these potential sites, in the present work, the effect of succinic acid

on thermal, optical, mechanical properties of KHP have been analyzed. The grown

crystals were subjected to different characterization such as single crystal XRD,

Powder XRD, UV-visible absorption study, FTIR spectral studies, Micro hardness,

and SEM.

2. Experimental

2.1. Synthesis and Growth

The KHPSA salt was obtained from an aqueous solution containing potassium

hydrogen phthalate and succinic acid in a 1:1 molar ratio. The calculated amount of

starting materials for the synthesis was obtained according to the reaction.

K(C6H4COOH-COO)+C4H6O4 KC8H5O4. C4H6O4

The calculated amount of KHP was first dissolved in Millipore water of 18.2

MΩ cm resistivity. The calculated amount of succinic acid added to the solution

slowly and stirred well using a temperature controlled magnetic stirrer about 18

hours to yield a homogenous mixture of solution. Then it was double times filtered

with Wattmann filter paper and poured into petri dishes. Then the filtered solution

74

was allowed to evaporate at room temperature and the mixed salt was obtained by

slow evaporation technique. The purity of the synthesized salt was further improved

by successive recrystallization process. By this method the seed obtained has been

used for the bulk growth. A good quality single crystal with size 13 × 5 ×2 mm3 was

harvested at the period of 23 days with appropriate growth rate of 0.56 mm/day. The

photograph of as grown KHPSA crystal is shown in figure 1.

Fig 1. Grown KHPSA Crystals

3. Result and Discussion

3.1 Single Crystal X-ray Diffraction Studies

The grown KHPSA crystals were studied intensively since they started to be

used as X-ray monochromator and X-ray analyzers. A fine quality KHPSA crystal

was kept on an Xcalibur, Eos diffractometer at 293(2) K. Single crystals X-ray

diffraction analyses of this single crystal have been carried out and the unit cell

parameter values are given in the table 1.

Table 1. Comparison of Unit Cell Parameter Values of KHPSA, Pure KHP and

Succinic Acid

Crystal a(Å) b(Å) c(Å) V(Å3) Crystal

system

Space

group

KHPSA 5.54 7.71 8.6 367 Orthorhombic P

Pure

KHP 6.46 9.57 13.28 828.831 Orthorhombic P21

SA acid 7.0511 9.7836 4.6868 341.62 Triclinic P21

75

From the result it has been found that the unit cell parameters of KHPSA are

decreased with respect to pure KHP, as shown in Table 1. The change in unit cell

volume of KHPSA with respect to pure KHP confirmed that the doping of succinic

acid into KHP crystal. From the unit cell parameter values, the dependence of the

lattice parameter ‘b’ and the corresponding volume change, clearly reveal that the

crystal undergoes non-uniform strain due to the presence of dopant.

3.2 Powder X-ray Diffraction

Powder X-ray pattern for NLO single crystal was recorded and shown in

figure 2. To identify the reflection planes and to check the crystalline perfection of

the grown crystal, powder X-ray diffraction patterns of the powdered sample have

been recorded using a Reich Seifert diffractometer with CuKα (λ = 1.5418 Ǻ)

radiation at 30 kV, 40 mA. The synthesized grown crystal was scanned over the

range from 10° to 80° diffraction angle at a scan rate of 2 % minute at room

temperature.

0 10 20 30 40 50 60 70 80 90

0

5000

10000

15000

20000

25000

Inte

nsity

(a.u

)

2 Theta(deg)

Fig 2. Powder X-ray Diffraction Pattern of KHPSA Crystal

The indexed pattern of KHPSA crystal consists a set of prominent sharp peaks

as shown in figure 2. The well-defined peaks at specific 2-theta values show high

crystalline of the grown crystal.

76

3.3 FT-IR Spectral Studies

The FTIR is used to identify the different functional groups present in the

compound of the grown crystal. The FTIR spectrum of KHPSA crystal was recorded

in the region 500–4000 cm-1 from KBr pellets on a Perkin Elmer FTIR

spectrometer as shown in figure 3.

Fig 3. FT-IR Spectrum of KHPSA Crystal

The band 2885cm-1 has been assigned to the C-H stretch. The 2648 cm-1 is

characteristic of C-H stretch. The other peak at 2522 cm-1 is assigned to O-H

bending. The peak at 1949 cm-1 represents C=C asymmetric stretch. The peak at1680

cm-1 represents -C=C- stretching. The peak at 1579 cm-1 is assigned to N-H bending.

The peak at 1398 cm-1 is assigned to C-C stretching. The very strong peak observed

at 1279 cm-1 is attributed vibration of the C-H Wag. The peak at 1071 cm-1 is

assigned to C-N stretching. The predominant peaks appeared between 903 and 553

cm-1 may be due to the vibrations involved by metal atoms in the crystal [11].

3.4 Optical Absorption Spectra

The optical absorbtion spectrum of the grown KHPSA was recorded using

Perkin Elmer Lambda 35 UV-Visible spectrophotometer in the wavelength range

from 200 to 900 nm. The recorded spectrum is shown in figure 4. The KHPSA

crystal has the lower cut-off wavelength at 210 nm in the UV region. The crystal

77

does not exhibit any absorption band in the entire visible region up to 850 nm. The

spectrum exhibits the strong absorption peak at 210nm. The absorption peak at 210

nm is assigned to π and π* transition of the compound. Absence of absorption

between 220 nm and 870 nm is an advantage, as it is the key requirement for

materials possessing SHG properties. As a result, it can be used as a potential

candidate for the SHG device applications in the visible region [12].

Fig 4. UV-Vis Absorption Spectra of KHPSA Crystal

3.5 Thermal Analysis

In order to study the thermal stability of the grown crystals, thermo

gravimetric (TG) and differential thermal analysis (DTA) have been carried out

using a Seiko TG-DTA 6200 model thermal analyzer in an inert nitrogen

atmosphere. Powdered sample of about 3.374 mg was used for the analysis in the

temperature range of 30 - 500°C with a heating rate of 20°C/minute. The TG-DTA

pattern recorded for the KHPSA crystal as shown in figure 5.

78

Fig 5. TG-DTA Curves of KHPSA Crystal

The above TG curve major weight loss occur at three stages. First weight loss

occur with 88.44% at 94 °C. The second weight loss occurs with 43.50% at 65°C

and the third weight loss occur with 38.41% at 52 °C. The weight losses are

conformed for sharp endothermic peaks of a DGTA trace. The three endothermic

peaks occurring at different temperatures. These three different stages indicate the

decomposition of the substance. This indicates that the crystal have high melting

point (188.82 °C) and it exhibit high thermal stability.

3.6 Micro hardness Test

The micro hardness testing is a characterization technique that can be well

suited to study the mechanical properties of the material, such as fracture behavior,

yield strength, brittleness index and temperature of cracking [13].

The indenter load ‘P’ is related with micro hardness number ‘Hv’by using the

relation

Hv = 1.8544 (P/d2) kg/mm2 --------------------- (3.1)

Where ‘d’ is the mean diagonal length of the impression in mm. The relation

between ‘Hv’ and ‘P’ for the grown crystals has been shown in figure 6.

79

1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50-2.1

-2.0

-1.9

-1.8

-1.7

-1.6

-1.5

-1.4

-1.3

-1.2

Log

P

Log d

Fig 6. Variation of Hardness Hv with load P for KHPSA Crystal

The Mayer’s index number or work-hardening coefficient ‘n’ was calculated

from the Mayer’s law [14], which relates the load (P) and indentation diagonal

length (d). P = kdn ------------------- (3.2)

where ‘k’ is the material constant. To estimate the work hardening coefficient

‘n’, for KHPSA crystal. Graph is drawn between log ‘d’ and log ‘P’ as shown in

figure 7.

Fig 7. Variation of log ‘d’ against log ‘p’ for KHPSA Crystal

The slope of the curves, after least square fitting, gives the value of ‘n’. The

‘n’ value of KHPSA crystal were found to be 2.06. The value is more than 1.6 it is

concluded that the crystals belong to soft category material [15].

80

3.7 SEM with EDS Analysis

SEM analysis provided information about the nature, suitability for device

fabrication and also it is used to check the presence of imperfections. SEM analysis

was carried out using JEOL JSM-5610 LV scanning electron microscope with an

accelerating voltage of 20 KV, at high vacuum mode and secondary electron image

(SEI). Since semi organic crystals are non-conducting in nature, gold coating (JEOL

auto fine Coater JFS-1600) was done for 120 s before subjecting KHPSA crystal

surface to electron beam [16]. KHPSA crystal has well developed morphology with

several habit faces (Figure 8). It exhibiting layered growth and it is observed that the

basic units are arranged in different layers, which is a clear evidence for the stacking

of fundamental units during crystal growth. KHPSA crystal was also analysed by

energy dispersive spectroscopy (EDS) for qualitative and quantitative information

and shown in figure 9. From the EDS spectra potassium (k) metal present in the

KHPSA crystal.

Fig 9. EDS Spectrum of KHPSA Crystal

4. Conclusion

Good quality single crystals of the succinic acid doped KHP crystal were

grown by slow evaporation solution growth technique. Lattice parameters were

calculated from the XRD characterization to compare with pure KHP and succinic

acid. Powder XRD studies reveals thatthe grown KHPSA crystal is having good

crystallinity. The optical transmission spectrum showed that succinic acid doped

KHP crystal has good transparency in the UV-Vis. The FTIR spectrum reveals the

81

various functional groups present in the grown crystal. The TG/DTA analysis shows

that the thermal stability of the grown KHPSA crystal. Vicker's micro hardness

studies were determined the KHPSA crystal found to be soft material category. The

surface morphology and some elemental compositions of the crystal were reported

by SEM with EDS analysis.

References

1. Wiliams, J., 1983. American Chemical Society Symposium Series 233,

American Chemical Society. Washington. DC.

2. Chemla, DS., Zyss, J., 1987. vol (1-2), Academic press, New York.

3. Kumaresan, P., Moorthy Babu, S., Anbarasan, PM., 2008. Optical Materials.

30, 1361-1368.

4. Okaya, Y., 1965. Acta Crystallogr. 19, 879.

5. Timpanaro, S., Sassella, A., Borghesi, A., Porzio, W., Fontaine, P.,

Goldmann, M., 2001. Adv. Mater. 13, 127.

6. Haber, T., Resel, R., Thierry, A., Campione, M., Sassela, A., Moret, M.,

2008. Physica E41, 133.

7. Oaki, Y., Imai, H., 2005. Chem. Commun. 48, 6011.

8. Kejalakshmy, N., Srinivasan, K., 2003. J. Phys. D, Appl. Phys. 36, 177.

9. Miniewicz, A., Bartkiewicz, S., 1993. Adv. Mater. opt. EWlectron. 2, 157.

10. Kejalakshmy, N., Srinivasan, K., 2004. Opt. Mater. 27, 389.

11. Petrosyan, AM., Sukiasyan, RP., Karapetyan, HA., Terzyan, SS., Feigelson,

RSJ., 2000. Crystal Growth, 213, 103.

12. Kirubavathi, K., Selvaraju, K., Vijayan, N., Kumararaman, S., 2008.

Spectrochim. Acta A, 71, 288.

13. Sharda, J., Shitole and Saraf, K., 2001. B Bull. Mater Sci., 24, 461-468.

14. Chacko, E., Mary Linet, J., Mary Navis, S., Priya, C., Vesta, B. 2006. Milton

Boaz, S. Jerome Das, Indian. J. Pure Appl. Phys, 44, 260.

15. Gong, J., 2000. Mater. Sci. Lett, 19, 515.

16. Jerald Vijay, R., Melikechi, N., Rajeshkumar, T., Jesudurai, M., Sagayaraj, P.,

2010. J. Cryst Growth. 420-425

82

GROWTH AND IN-VITRO STUDIES ON CYSTINE URINARY STONE IN

SILICA GEL MEDIUM

M.Saravana Kumar1* and F.Liakath Ali Khan2 1Department of Physics, Muthurangam Govt. Arts College, Vellore, Tamilnadu,

India. 2Department of Physics, Islamiah College, Vaniyambadi, Tamilnadu, India.

Abstract

Cystine is found rarely (about 1%) in urinary stones. These crystals were

grown by the single diffusion gel growth technique in sodium metasilicate gel.

The crystals were found to be having single, twinned and bunched hexagonals,

cubic, rectangular, bipyramidal and needles morphologies were obtained.

Crystal of hexagonal morphology, structure and elemental composition of the

grown crystals have been analyzed using SEM -EDAX and powder XRD

studies. Functional groups present in the grown crystals have been confirmed

from the FTIR spectrum. This was in agreement with earlier reported studies.

Key words: Urinary stones, Cystine crystal, growth parameters, Powder XRD, FTIR,

surface morphology ,EDAX and thermal studies.

1. INTRODUCTION

The pathological mineralization may be defined as crystal deposition diseased

associated with the presence of microcrystals which contribute to tissue damage and

cause pain and suffering. Significance of the in vitro investigation of the urinary

stone mineralization on human body was employed by Nancollas et al., 1992.

Kidney stones developed by various metabolic and environmental-nutritional

factors including hypercalciuria, hyperoxaluria, hyperuricosuria, hypercitraturia,

under urinary acidity, cystinuria and low urine volume. For the treatment of

urolithiasis, there are different drugs are used such as thiazide diuretics, potassium

citrate, low calcium diet for hypercalciuria, allopurinol for hyperuricosuria,

magnesium citrate for hyperoxaluria, chelating agents for cystinuria and antibiotics

for infection stones. (Pak CYC et al 1976).

83

2. MATERIALS AND METHOD

A gel is defined as a two component system of a semi-solid in nature, rich in

liquid. It is also termed as loosely inter-linked polymer. Importances of gel medium

are as follows

Crystal can be grown in room temperature. Hence it will have lower concentration of

non- equilibrium defects, than those grown at elevated temperature. Crystal can be

observed practically in all stages of growth. It forms three dimensional structure

entrapping water. It remains chemically inert, prevents turbulence. Rate of reaction is

controlled. Concentration of reactants can be easily varied. Crystals of different

morphologies and sizes can be obtained by changing the growth condition. The

grown crystal can be easily harvested, without damaging the crystal face. This

method is extremely simple and inexpensive. Silica gel is the best and most versatile

growth media (Henisch, 1988).

A stock solution of sodium meta silicate is prepared by adding 100ml of

distilled water to 60 grams of sodium meta silcate powder (Na2SiO3.9H2O). Using

this solution one can prepare gels of various specific gravity. Very dense gels

produce poor crystals and gels of insufficient density take a long time to form crystal

and are mechanically unstable. A specific gravity of 1.04g/cm3 appears to be the

ideal value to grow cystine crystals.

3. GROWTH OF CYSTINE CRYSTALS

Cystine crystals were grown by gel method (Girija et al., 1995). Solution was

prepared by dissolving a small amount of L-Cystine in sodium meta silicate of

specific gravity 1.04 g/cc and then pH was adjusted to 6.0 by treating it with glacial

acetic acid and the solution was allowed to set. Crystals of cystine having different

morphologies viz., single, twinned and bunched hexagonals, cubic, rectangular,

bipyramidal and needles were obtained.

84

Fig.1. As grown crystal Fig.2. Harvested crystal

4. Results and discussion

4.1.Powder XRD analysis

The powder X-ray diffraction pattern of hexagonal shaped crystal is shown

in Fig. 3. The d values obtained from the reflections of harvested crystal agree well

with that of cystine (JCPDS, PDF No. 23-1663). The cystine crystals belong to

hexagonal system with space lattice P6122. Lattice parameters, a = 5.436 Å and c

= 56.37Å (Goldfarb et al., 2006).The powder XRD patterns of gel grown urinary

crystals is shown in figure 3.

4.2 FTIR spectrum of Cystine crystal

FTIR spectrum is recorded IR spectrum of cystine (Figure 4) using KBr pellet

method. The absorption band at 3026 cm-1 has been assigned to CH stretching

vibrations. The two bands at 1622 and 1584 cm-1 are assigned to NH, deformation.

The band observed at 1408 cm-1 is related to the mixed vibrational modes of C-H

bending and COO- stretching modes. The bands at 1382 cm-1 and 1337 cm-1 has

been assigned to C-H bending and C-C stretching, respectively. C-S stretching

vibration is seen at 675 and 615 cm-1. The sharp band at 540 cm-1 is attributed to the

S-S stretching mode. This is in well agreement with the result of Girija et al., 1995.

85

Fig.3. Powder XRD of Cystine crystal Fig.4. FTIR spectrum of Cystine crystal

Fig.6. SEM Picture of Cystine crystal Fig.7. EDX Pattern of Cystine crystal

4.3 SEM and EDX studies

Figure 5 & 6 represent the SEM and EDAX analysis of gel grown

Cystine crystal. From this one may conclude that cystine crystals exhibits hexagonal

surface morphology and the elemental composition of the grown crystal were

identified by EDAX analysis. The Energy Dispersive X-ray Spectroscopy (EDX)

86

analysis of cystine crystal revealed the presence of 42.857% of Carbon atoms

along with expected Oxygen (28.571%), nitrogen and sulphur (14.286%).

5. CONCLUSION

Cystine crystals have been grown in SMS gel. Growth parameters are

standardized. Powder XRD analysis confirm the crystal nature of the gel grown

crystal and the lattice parameters have been determined. FTIR studies reveal the

presence of various functional groups. Surface morphology and compositional

details are studied using SEM and EDX studies.

References

1. Heinz. K. Henisch, “ Crystals in Gels and Liesegang Rings”, Cambridge

University press, (1988).

2. George H. Nancollas, The involvement of calcium phosphates in biological

mineralization and demineralization processes , Pure & Appl. Chern., 64(11),

1673-1678, (1992).

3. Girija. E.K, Narayana Kalkura. S and Ramasamy.P, Crystallization of cystine,

Journal of Materials Science: Materials in Medicine, 6, 617-619, (1995).

4. Goldfarb D. S., Coe F. L. and Asplin J. R., Urinary cystine excretion and capacity

in patients with cystinuria. Kidney Int., 69, 1041-1047, (2006).

5. Pak, C. Y. C, Hayashi. Y and Arnold, L. H, Heterogenous nucleation between

urate, calcium phosphate and calcium oxalate, Proceedings of the Society of

Experimental Biology and Medicine, 153, 83–87, (1976).

siascphysics@gmail.com

87

CHARACTERIZATION AND THEORETICAL PROPERTIES OF DIHYDROXY COUMARIN, NLO SINGLE CRYSTAL BY DFT METHOD

K.Sambathkumara* , R.saradhaa, A.Claudea and K.Settua.

aP.G.&Research Department of Physics, A.A.Govt.Arts College, Villupuram-605602

ABSTRACT Dihydroxy coumarin (DHC), a semi-organic nonlinear optical material, has been

synthesized and single crystals were grown from ethanol solution at room

temperature up to dimensions of 4.7cm×4.1cm×3cm. The unit cell parameters were

determined from single crystal and powder X-ray diffraction studies. The structural

perfection of the grown crystal has been analyzed by X-ray diffraction (XRD) study.

The variation of dielectric properties of the grown crystal with respect to frequency

has been investigated at different temperatures. Microhardness measurements

revealed the mechanical strength of grown crystal. The optical parameters, the

optical band gap Eg and width of localized states Eu were determined using the

transmittance data in the spectral range 200–800 nm. The relative second harmonic

efficiency of the compound is found to be 1.4 times greater than that of KDP and

ADP. Static deformation, dynamic deformation & Laplacian map are also

constructed. And the theoretical studies were conducted on the molecular structure

and vibrational spectra of vinyl benzoate (DHC). The FT-IR and FT-Raman spectra

of DHC were recorded in the solid phase. The molecular geometry and vibrational

frequencies of DHC in the ground state have been calculated by using the density

functional methods (B3LYP) invoking 6-311++G(d,p) and 6-311+G(d,p) basis set.

The optimized geometric bond lengths and bond angles obtained by DFT method

show best agreement with the experimental values. A detailed interpretation of the

FT-IR and FT- Raman, spectra of DHC was also reported. Such as HOMO and

LUMO energies, were performed by time dependent density functional theory (TD-

DFT) approach. Finally the calculations results were applied to simulated infrared

and Raman spectra of the title compound which show good agreement with observed

spectra.

Keywords: FTIR, FT-Raman, HOMO- LUMO, MEP, DHC. *Corresponding author. E-mail address: sa75kumar@yahoo.co.in(K.Sambathkumar)

88

Introduction The dimer of dihydroxy coumarin moiety (Figure 1) is a common fused

heterocyclic nucleus found in many natural products of medicinal importance.

Several of these natural products exhibit exceptional biological and pharmacological

activities such as antibiotic, antiviral, anti-HIV, anticoagulant and cytotoxicity

properties. Additionally, coumarin derivatives have been used as food additives,

perfumes, cosmetics, dyes and herbicides. Recently, Supuran et al. reported that

coumarin derivatives constituted a totally new class of inhibitors of the zinc

metalloenzyme carbonic anhydrase. Additionally, two new series of dihydroxy

coumarin analogues have been synthesized as inhibitors of the enzyme of human

NAD(P)H quinine oxidoreductase-1 (NQO1), which is expressed in several types of

tumor cells[1]. A series of coumarins bearing different groups on the aromatic ring

were synthesized and tested as caspase activators and apoptosis inducers, showing

that these compounds can be used to induce cell death in a variety of conditions in

which uncontrolled growth and spread of abnormal cells occurs. Moreover, coumarin

dyes have attracted much interest owing to their application in organic light-emitting

diodes (OLEDs). As a result of showing a wide range of size, shape and

hydrophobicity, coumarins are used as sensitive fluorescent probes of systems

including homogeneous solvents and mixtures and heterogeneous materials. In

addition, they form host-guest inclusion complexes with cage-like molecules such as

cyclodextrins and cucurbiturils . The interest in the biological activity of dihydroxy

coumarin continues nowadays, with warfarin and acenocoumarol being two of these

derivatives which have been marketed as drugs. Warfarin has been the mainstay of

anticoagulation therapy worldwide for over 20 years, therefore a series of similar

derivatives have been synthesized and tested as anticoagulant agents.

Acenocoumarol acts in the same way, therefore several dihydroxy coumarin

derivatives have been synthesized and their pharmacological activity was tested[2].

Results and Discussion

As part of our program studying the chemistry of fused heterocyclic systems

with specific functional groups we wish to report herein an extended methodology

for the synthesis of3-functionalized-dihydroxy coumarin, applying as alternative and

89

ultimate scaffold, the N-hydroxysuccinimide ester of O-acetylsalicylic acid, for the

“coupling reaction” with an active

methylene compound. The chemistry proceeds via a tandem intermolecular

nucleophilic coupling of the N-hydroxysuccinimide ester of O-acetylsalicylic acid

with an active methylene compound, and the subsequent intramolecular cyclization

of the intermediate to a stable six-membered ring system, the coumarin nucleus, as

shown in Fig 1.This approach would provide an alternative general method for the

synthesis of coumarins and other similar organic molecules containing the

benzopyranone ring system. The proposed protocol involves the following steps: a)

the deprotonation of an active methylene compound; b) the nucleophilic attack at the

carbonyl of the N-hydroxysuccinimide ester; c) the in situ intramolecular cyclization

of the “intermediate” precursor affording the functionalized heterocycles bearing the

coumarin nucleus. The key control element of this approach is the utilization of the

N-hydroxy-succinimide ester of O-acetylsalicylic acid. This acylating agent was

synthesized by condensation of equimolar amounts of O-acetyl-protected salicylic

acid and N-hydroxy succinimide (NHS) in the presence of 1.2 equiv. of dicyclo

hexylcarbodiimide (DCC) in anhydrous tetrahydrofuran at 0 °C. This excellent

activating synthon was isolated in good yields as a white solid and was used in the

next step without further purification. The C-acylation protocol involved the reaction

of 2 equiv. of an active methylene compound with 2 equiv. of sodium hydride in

anhydrous tetrahydrofuran at0 °C. After 1 hour of continuous stirring, 1 equiv. of the

N-hydroxysuccinimide ester was added and the mixture was stirred for 2 hours, at

room temperature. In consequence, the solvent was removed under reduced pressure,

the gummy solid was diluted with water, washed with diethyl ether and the aqueous

layer was acidified with aq. solution of hydrochloric acid 10%, to give after

extraction with dichloromethane, the intermediates as oily products. Cyclization of

these C-acylation compounds was affected by refluxing them with two-fold excess

amount of sodium ethoxide in ethanol for 24 h or by mixing them with aq. solution

of hydrochloric acid 10% in methanol for 48 h at room temperature. Several features

of the proposed methodology make it synthetically useful: the starting materials are

inexpensive and stable; the yields are good; the reactions are relatively rapid and

90

proceed at ambient temperature or under mild and easily controlled conditions.

Furthermore, the methodology can be expanded to other heterocyclic systems

bearing different heteroatoms or functions on the heterocyclic and/or aromatic ring.

X-ray Crystallographic Analysis

The crystal of this compound belongs to the monocyclic space group P2(1)/c. The

data were collected at 150(2) K on a Bruker Apex II CCD diffractometer using

MoKα radiation (λ = 0.71073 Å). The structure was solved by direct methods and

refined on F2 using all the reflections. Parameters for data collection and refinement

are summarized in Table 1. Crystallographic data of dihydroxy coumarin and

selected bond lengths and angles are given in Table 2. The crystal structure and

packing diagram of this compound are given in Figures 2 and 3 respectively. The

structure resembles with a double bond character in C(8)-C(9) (1.37 Å) and the bond

C(8)-O(3) distinctly longer than the conventional carbonyl distance for C(1)-O(1)

(1.31 Å and 1.19 Å respectively)[2]. The molecules show π-π stacking principally

with a planar distance of 3.9 Å.

HOMO–LUMO energy gap and related molecular properties

The interaction of two atomic (or) molecular orbitals produces two new

orbital. One of the new orbitals is higher in energy than the original ones (the anti

bonding orbital) and one is lower (the bonding orbital). When one of the initial

orbitals is filled with a pair of electrons (a Lewis base) and the other is empty (a

Lewis acid), we can place the two electrons into the lower, energy of the two new

orbitals. The "filled-empty" interaction therefore is stabilizing. When we are dealing

with interacting molecular orbitals, the two that interact are generally the highest

energy occupied molecular orbital (HOMO) and lowest unoccupied molecular

orbital (LUMO) of the compound. These orbitals are the pair of orbitals in the

compound, which allows them to interact most strongly. These orbitals are

sometimes called the frontier orbitals, because they lie at the outermost boundaries

of the electrons of compound. The HOMO-LUMO analysis for the title compound

has been carried out using B3LYP/6-311++G(d,p) method. The computed values of

HOMO and LUMO are tabulated in Table 3. From the table shows that energy gap

91

explains the eventual charge transfer within the molecule. The HOMO-LUMO plots

are shown in Fig 4. In this investigation, the more relevant electronic potential (IP),

electron affinities (EA), chemical potential (µ) it is the negative of electro negativity

(χ), hardness (η), softness (S), electrophilic index(ω) and the electric dipole

polarizability (α) were calculated. The ionization potential is calculated as the energy

difference between the energy of the molecule derived from electron-transfer (radical

cation) and the respective neutral molecule; IP = Ecation - En. The EA was

computed as the energy difference between the neutral molecule and the anion

molecule: EA = En+ Eanion . The HOMO and LUMO energy was also used to

estimate the IP and EA in the framework of Koopmans’ theorem:

IP = -εHOMO and EA= - εLUMO

Within the framework of the density functional theory (DFT), one of the global

quantities is chemical potential (µ), which is measures the escaping tendency of an

electronic cloud, and equals the slope of the Energy versus N(number of electrons)

curve at external potential ν(r)[3] :

µ = (E/N)V(r)

Finite difference approximation to Chemical Potential gives,

= -µ = -(E/N)V(r)

The theoretical definition of chemical hardness has been provided by the density

functional theory as the second derivative of electronic energy with respect to the

number of electrons N, for a constant external potential ν(r)[4] :

η = ½(2E/N2)V(r) = ½( µ/N)V(r)

Finite difference approximation to Chemical hardness gives,

η = ( I-A )/2

For Insulator and semiconductor, hardness is half of the energy gap (εHOMO - εLUMO ),

and the

softness is given as :

S = 1/2η=(2E/N2)V(r)= (E/N)V(r)

92

Electrophilicity index is a measure of energy lowering due to maximal electron flow

between donor and acceptor. Electrophilicity index (ω) is defined as,

= µ2/2 η

B3LYP functional used in this study has a high efficient to calculate the electronic

properties for the organic studied molecules, such as ionization potentials (IP),

electron affinities (EA), electro

negativity (χ), absolute hardness (η), absolute softness (S), electrophilic index

(ω)[3]. The first one being energy-vertical is based on the differences of total

electronic energies when an electron is added or removed in accordance with the

neutral molecule. The second one is based on the differences between the HOMO

and the LUMO energies of the neutral molecule and is known as orbital-vertical

(Koopmans’ theorem). Therefore, the Koopmans’ theorem is a crude but useful and

fast approach. The behavior of electro negativity, softness and electrophilic index for

the studied molecules shows the magnitude large than these for the original ring,

adding the radicals give the molecule more softness.

Molecular electrostatic potentials (MEP)

Molecular electrostatic used extensively for interpreting potentials have been

and predicting the reactive behavior of a wide variety of chemical system in both

electrophilic and nucleophilic reactions, the study of biological recognition processes

and hydrogen bonding interactions [5].

V(r), at a given point r (x,y,z) in the vicinity of a compound, is defined in

terms of the interaction energy between the electrical charge generated from the

compound electrons and nuclei and positive test charge ( a proton) located at r.

Unlike many of the other quantities used at present and earlier as indices of

reactivity, V(r) is a real physical property that can be determined experimentally by

diffraction or by computational methods. For the systems studied the MEP values

were calculated as described previously, using the equation:

V( r) = ZA/RA-r-(r’)/ r’-rdr’

93

where the summation runs over all the nuclei A in the compound and polarization

and reorganization effects are neglected. ZA is the charge of the nucleus A, located at

RA and (r’) is the electron density function of the compound.To predict reactive

sites for electophilic and nucleophilic attack for the investigated compound,

molecular electrostatic potential (MEP) was calculated at B3LYP/6-31++G(d,p)

optimized geometries. Red and blue areas in the MEP map refer to the regions of

negative and positive potentials and correspond to the electron-rich and electron-

poor regions, respectively, whereas the green color signifies the neutral electrostatic

potential. The MEP surface provides necessary information about the reactive sites.

The electron total density on to which the electrostatic potential surface has been

mapped is shown in Fig.5, the electron density isosurface being 0.002 a.u. The

negative regions V(r) were related to electrophilic reactivity and the positive ones to

nucleophilic reactivity. As easily can be seen in Fig.6, this compound has several

possible sites for electrophilic attack in which V (r) calculations have provided in-

sights. Negative regions of V(r) are associated with chlorine and oxygen atoms of

DCH [6]. The most negative V(r) value is associated with carbon atoms in the ring of

DCH. Thus, it would be predicted that an electrophile would preferentially attack

DCH at these position. Alternatively, we found the positive regions over the

hydrogen atoms of DCH compound and indicating that these sites can be the most

probably involved in nucleophilic processes. The Fig 7 shows the molecular

electrostatic potential surface of (DCH). The colour–coded values are then projected

onto the isodensity surface to produce a three–dimensional electrostatic potential

model. Local negative electrostatic potentials (red) signal oxygen atoms with local

positive electrostatic potentials (blue) signal polar hydrogen the in ring. Green areas

cover parts of the molecule where electrostatic potentials are close to zero (C–C and

C–Cl bonds).

Conclusion

The XRD studies confirm the structural identity of the grown crystals. The HRXRD

study indicates that the grown crystal has very low angle boundary. FT-IR and FT-

Raman spectra revealed the presence of various functional groups. So we carried out

94

ab initio and density functional theory (B3LYP) calculations on the structure and

vibrational spectra of HDP. The vibrational frequencies analysis by B3LYP method

agrees satisfactorily with experimental results. On the basis of agreement between

the calculated and experimental results, assignments of all the fundamental

vibrational modes of DHC were examined and proposed. Therefore, the assignments

made at higher level of the theory with higher basis set with reasonable deviations

from the experimental values, seems to correct. HOMO and LUMO energy gap

explains the eventual charge transfer interactions taking place within the compound.

NLO property has also been observed by predicting the first hyperpolarizability for

the title compound due to the substitution in the benzene. MEP study shows that the

electrophilic attack takes place at the C5 position of HDP compound.

Table1 Crystal data and structure refinement for Dihydroxy coumarin Empirical formula C11H8O5 Formula weight (g.mol-1) 162.2 Crystal size/mm 0.40×0.21×0.18 Crystal system Monoclinic Space group P2(1)/c Unit cell dimensions a (Å) 3.8056(3) b (Å) 8.4552(7) c (Å) 11.3651(10) α (°) 90 β (°) 95.629(4) γ (°) 90 V (Å3) 363.93(5) Z 2 µ (mm−1) 0.369 Dc/g cm-1 1.48 (sinθ /λ )max/Å-1 1.08 Reflections collected 6373 R(F); Rw(F) 0.0158; 0.0145 S 1.41 Nobs/Npar 20.14 Largest difference in peak and hole (eÅ-3)

-0.203; 0.324

95

Table 2Optimized geometrical parameters of Dihydroxy coumarin by HF /6-311++G(d,p) and B3LYP/6-311++G(d,p) calculations Value (A0) Value ( 0 ) Value ( 0 )

Bond Length

HF /6-311 ++G(d,p)

B3LYP/6-311++G(d,p)

Exp Bond Angle HF /6-311

++G(d,p)

B3LYP/6-311++G(d,p)

Exp

Dihedral Angle HF /6-311 ++G(d,p)

B3LYP/6-311++ (d,p)

Exp

N6-H7 0.99 1.01 0.84

H4-O3-C18 108.3 106.5 109.4 H4-O3-C18- O2 0.2 0.3 -4.3

N6-C19 1.36 1.38 1.37

O3-C18-O2 120.1 119.8 122.2 O3-C18-C9-C10 -0.6 0.5 5.8

N6–C8 1.39 1.39 1.40

C9-C8-N6 119.2 118.9 118.8 H4-O3-C18-C9 179.9 180.0 175.5

O3-H4 0.95 0.97 0.84

C8-N6-H7 113.9 112.8 114.0 C8-N6-C19-O5 3.8 2.9 -2.0

C19-O5 1.20 1.22 1.22

C8-N6-C19 128.9 129.0 129.1 H7-N6-C19-O5 -180.0 -179.9 176.0

C19-C20

1.50 1.50 1.51

H7-N6-C19 117.4 118.3 116.0 O5-C19-C20-C28 180.0 -179.9 176.0

C25-C23

1.38 1.39 1.39

N6-C19-O5 124.4 123.6 124.7 Cl1-C25-C23-H24 0.8 0.7 -0.2

C18-O2 1.20 1.23 1.23

O5-C19-C20 120.4 120.7 121.0 Cl1-C25-C23-C21 -180.0 180.0 179.8

Cl1-C25 1.72 1.73 1.74

H29-C28-C26 117.9 117.3 119.7 Cl1-C25-C26-C28 180.0 -180.0 -0.5

Cl1- O2 1.7418 1.7556 1.42

Cl1-C25-C23 119.5 119.5 119.3 C20-C19-N6-C28 180,0 -179,9 177.2

O2- O3 1.3806 1.3911 1.53

Cl1-O2- O3 119.4057 119.3931 123.6 Cl1-O2-O3-H4 -179.7711 -179.8714

O2- H7 1.3831 1.3925 Cl1-O2- H7 119.4234 119.4678 120.7 Cl1-O2-H7-N6 -179.7807 - 179.8672 178.4 O3- H4 1.3846 1.3919 0.8

5 O3-H4 -O5 120.6348 120.7201 116.3 O2-O3-H4-O5 -0.2058 -0.0653 -

176.5 O3- C8 1.0731 1.0823 O3-H4 -C9 17.8304 117.6575 118.5 O2 -O3-H4-C9 -179.2518 -179.2295 174.4

96

H4- O5 1.3893

1.4007 H13-C12- C1 115.0855 4123.9514 H13-C12-C14-C25 174.4246 175.9823 -174.5

H4- C9 1.0741 1.0836 1.22

C12-C14-H15 128.9167 128.9882 C12-C14-H15-C16 -179.5643 -179.9669 179.4

O5- N6 1.3901 1.4 1.53

C12-C14-C25 117.1009 117.9541 H13-C12-C14-C25 174.4346 175.9823

O5- C12 1.5058 1.5054 1.28

C14-H15- C20

122.2628 122.3926 C25-C14-H15-C20 -177.5602 -178.8716

N6- C10 1.0728 1.0826 1.20

H17-C16- C26

118.3867 119.0693 H17-C16-C26-H27 -179.1265 -179.3931

H7- H11 1.0733 1.0824 1.53

C16-H17- C18

121.5012 121.3318 C16-H17-C18-H22

-179.9907 -179.9907

C12- H13

1.1946 1.221 1.10

C16-H17- C21

119.8565 118.4534 119.3 H15-C16-H17-C21

-179.5552 179.9864

C12- C14

1.3652 1.3806 H17-C18- C19

118.5303 118.9655 121.6 C26-H17-C18-C19

178.5942 179.5942

H13- H24

2.154 2.1421 H17-C18- H22

120.5065 120.294 120.7 C21-H17-C18-H22 -0.0763 -0.0971

C14- H15

1.3948 1.3956 C19-C18 -H22

120.9631 120.7405 115.3 C19-C18-H22-C20 -179.9204 -179.9204

C14- C25

0.9933 1.0156 C18-C19- C20

121.5876 121.332 C18-C19-C20-H24

179.7162 179.7709

H15- C16

1.4122 1.4264 C18-C19- C23

119.8897 119.9431 C16-C26-H27H29 -179.1265 - 179.9771

H15- C20

1.3963 1.4057 C20-C19-C23 118.5227 118.7249 C16-C26-C28-C23 179.5888 179.9888

C16- H17

1.3964 1.4053 H15- C20-C24

119.4354 118.6987

97

Table 3 HOMO - LUMO energy gap and related molecular properties of Dihydroxy coumarin.

Molecular Properties

HF/6-311++G(d,p) B3LYP/6-311++G(d,p)

HOMO -0.3204a.u -0.2626a.u

LUMO -0.0743a.u. -0.0942a.u.

Energy gap 0.2461a.u. 0.1683a.u.

Ionisation Potential (I) 0.3204 a.u. 0.26261a.u.

Electron affinity(A) 0.0743 a.u. 0.9425a.u.

Global softness(s) 8.1267a.u. 11. 8793a.u.

Global Hardness (η ) 0.1230 a.u. 0.0841a.u.

Electro negativity (χ) 0.1973a.u. 0.1784 a.u.

Global Electrophilicity (ω) 1.5821a.u. 1.0598 a.u.

Fig 1 Dimer molecular structure of Dihydroxy coumarin

98

Fig 2 ORTEP diagram with labels for atoms Dihydroxy coumarin.

Fig 3 Static deformation density maps drawn in the plane Dihydroxy coumarin.

99

Fig. 4: HOMO-LUMO plot of Dihydroxy coumarin

∆E = 0.1683a

(First excited state)

ELUMO = -0.2626 a.u

(Ground State)

EHOMO = -0.0942a.u

100

Fig 5 The total electron density surface of Dihydroxy coumarin

Fig 6 The contour map of electrostatic potential surface of Dihydroxy coumarin.

101

Fig 7 The molecular electrostatic potential surface of Dihydroxy coumarin.

Reference

[1]M. Arivazhagan, K. Sambathkumar and S. Jeyavijayan, Indian J. Pure Appl. Phys., 48

(2010) 716-722.

[2]D.Cecily Mary Glory, R.Madivanane and K.Sambathkumar Elixir Comp. Chem. 89

(2015)

36730-36741.

[3] Kuppusamy Sambathkumar Spectrochim. Acta A 147 (2015) 51-66.

[4]K. Sambathkumar, Density Functional Theory Studies of Vibrational Spectra, Homo-

Lumo, Nbo and Nlo Analysis of Some Cyclic and Heterocyclic Compounds (Ph.D.

Thesis), Bharathidasan University, Tiruchirappalli, August 2014.

[5]K.Sambathkumar and K.Settu Elixir Vib. Spec. 91 (2016) 38087-38098. [6]K.Sambathkumar and G.Ravichandran Elixir Comp. Chem. 91 (2016) 38077-38086 38077.

102

GROWTH AND CHARACTERIZATION OF POTASSIUM

THIOCYANATE DOPED POTASSIUM DI HYDROGEN ORTHO

PHOSPHATE (KSCN-KDP) CRYSTALS BY SR METHOD

B.Shalini

Department of Physics, Auxilium College, Gandhi Nagar, Vellore

ABSTRACT

Potassium thiocyanate doped potassium dihydrogen phosphate (KDP)

crystals were grown by Sankaranarayanan Ramasamy (SR) technique. The grown

crystals were characterized by powder X-Ray diffraction to find the phase and

structure of the crystals. The FTIR analysis was made to identify the functional

groups and the UV-VIS transmission studies were carried out to determine the

optical transparency of the grown crystals. And micro hardness are also determined.

Introduction :

A crystal is a three dimensional solid composed of a periodic array of atoms

i.e., a representative unit is repeated at regular intervals along any and all directions

in the crystals.[2] The beauty and sparkle of many faceted crystals found all over the

earth crust have attracted man’s interest since the beginning of recorded history.

Crystals have been attracting mankind in the past due to their aesthetic beauty.

Examples for them are the most valuable diamond to artificial stones like American

diamond. Recently, single crystals have been used extensively in solid state devices.

Today, crystals are the pillars of the modern technology. Without crystals, there

would be no electronic industry, no photonic industry, no fiber-optic

communications, very little modern optical equipment and some very important gaps

in conventional production engineering.[1]

Materials and methods: Potassium thiocyanate is the chemical compound with the

molecular formula KSCN and Potassium dihydrogen phosphate (KDP). Seed for

crystal growth were prepared by slow evaporation method. In this method, 300 ml of

double distilled water was taken in a 500 ml beaker in that KDP of 129.2855g and

KSCN of 4.859g was added. The substance (KSCN salt + KDP salt) was made to

dissolve in the solvent (water) until the formation of supersaturated solution. Then,

the highly dissolved salt solution was filtered and poured in a tray covered with a

103

plastic paper with a few small holes for evaporation of solvents. The apparatus was

placed undisturbed till sufficient size of seed crystal (KSCN + KDP) were obtained

in the tray. Finally the seeds were harvested for crystal growth as shown in the

Figure.

Seed crystal

Preparation of solution

Making up the solution is the most time consuming process. There appear to

be short cuts for obtaining a solution precisely equilibrated at a desired temperature,

but it may be helpful to mention some common pit fills. A precisely saturated

solution can never be made simply by combining the necessary amount of water and

salts as determined by solubility curves, first, because astonishingly larger amount of

published solubility data is not accurate, and second heating to complete dissolutions

introduces gross errors. Here a highly soluble KSCN doped KDP salt solution was

prepared in a 500 ml beaker by continuous stirring of KSCN doped KDP salt in

distilled water. After getting supersaturated solution, the solution was filtered and

poured in a beaker. The crystals were formed.

Solubility test: KSCN doped KDP was made to dissolve in water until the

formation of supersaturated solution. On reaching the supersaturation, the

concentration of the solute may be determined gravimetrically. A sample of the clear

super anent liquid was withdrawn by means of a warmed pipette and poured in a

petridish which has been covered with seal paper with small holes. After the

evaporation of solvent the remaining substance was weighed. The above procedure is

repeated for different temperature. Then the solubility graph was drawn.

104

Table1: Solubility of KSCN doped KDP

Temperat

ure (0C)

Solubility in

10 ml of

water (gms)

30 2.4126

35 2.6734

40 2.8928

45 3.1653

50 3.3661

Solubility diagram of KSCN doped KDP crystal at various temperatures

Harvesting the grown crystal by slow cooling method

This is the best method among others to grow bulk single crystals from solutions.

Already prepared synthesized material was taken and crushed well. The synthesized

substance was made to dissolved in solvent (water) till the formation of

supersaturated solution. Then the solution was filtered and poured in a beaker and

covered with seal paper with small holes. Crystal grown of suitable size by slow

cooling method was harvested carefully. The crystal thus obtained is shown in figure

4.4,

CON

CEN

TRAT

ION

TEMPERATURE IN oC

105

Crystal grown by slow cooling method

Harvesting the grown crystal

Crystal grown in suitable size by the Sankaranarayanan tube was harvested

carefully. The crystal thus obtained is shown in figure

Figure: Crystal grown by Sankaranarayanan method

Results and characterization: Powder XRD analysis. Powder XRD is useful for

confirming the identity of a solid material and determining crystalline and phase

purity. Figure 5.4 shows x-ray powder diffraction patterns of KSCN doped KDP.

Powder X-ray diffraction study was carried out using Rich Seifert X-ray

diffractometer with the CuKα radiation (λ = 1.5418 Å) in the range of 10 ° - 80 °, in

steps of 0.02 °. It reflects good crystallinity

of the grown crystal. The lattice

parameters were calculated using TREOR

program and the peaks were indexed using

APPLEMAN program from the observed 2

θ values. The calculated lattice parameters

shows that it belongs to tetragonal system

with the parameters a = 7.4557Å, b =7.4557Å, c = 6.9226Å, and Volume =

384.81Å, Density = 2.3325 g/cm3 the XRD spectrum of the KSCN doped KDP in

20 30 40 50 600

2000

4000

6000

8000

10000

12000

(321

)

(301

)

(220

)(1

12)

(211

)

(200

)

Inte

nsity

2 the ta

106

JCPDS 35-807. The calculated values were in best agreement with the reported

literature. The recorded spectrum is shown in fig

Figure X-ray powder diffraction pattern of KSCN doped KDP

hkl values of KSCN doped KDP were confirmed by Joint committee on powdered

diffraction studies (JCPDS).

Fourier Transform Infrared Spectroscopy analysis:

A Fourier transform infrared spectrum has been taken for the powder KDP crystal

using KBr pellet technique. The spectra were recorded in the wavelength ranges 400-

4000cm-1 and the graph is given below,

403.

1943

4.62

463.

0153

6.73

903.

98

1091

.69

1307

.4616

28.8

0

2465

.30

2929

.48

3444

.59

3653

.113692

.68

3750

.06

3783

.83

3894

.57

3994

.49

KDP

40

45

50

55

60

65

70

75

80

85

90

95

100

%T

500 1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)

Figure FT-IR spectroscopy

The functional groups of the sample have been analyzed by FT-IR spectrum.

The FT-IR spectra were recorded in the regions of 400 – 4000cm-1 using perkin-

elmer FT-IR spectrum RXI spectrometer by KBr petter technique. Figure 5.7 shows

the FT-IR spectrum of the sample. The peaks at particular wave number confirms

the functional groups of the sample. It includes O-H stretching vibrations of KDP.

Hydrogen bonding within the crystal is suggested to be cause for the broadening of

the peak. The presence of water is well supported by its bending vibrations in the

spectrum.

107

Assignment of some selected FT-IR wave numbers (Cm-1) of KSCN doped KDP.

1307.46 P=O stretching vibration, 903.98 P-O-H stretching vibration, 3614( band of

weak intensity) O-H stretching vibration, 3444.59 O-H stretching vibration,

2465.30-2929.48 (very weak band) P-O-H Symmetric stretching and bending,

536.73(very strong band) HO-P-OH bending vibrations.

UV visible analysis

200 300 400 500 600 700 800 900nm

KDP

0.00.51.01.52.02.53.03.54.04.55.0Abs

Figure UV-Visible absorption spectrum

The UV-visible absorption spectrum of the sample was recorded in solution

form using water solvent in the ratio of 1:1 (water : ethanol ). Fig. shows UV-visible

absorption spectrum of the sample. The cut off wavelength was observed at 250nm

and there was no significant visible spectrum in the range of 300 to 900nm.[7]

Internal structure of KSCN doped KDP crystal

Figure 5.11 Internal structure of KSCN doped KDP crystal

108

Internal structure of KSCN doped KDP crystal were found by using optical

microscope. In these figure number of pits and also voids are present.

Measurement of microhardness

Measurement of microhardness measurement of KSCN doped KDP crystal

Conclusions

Potassium thiocyanate doped potassium dihydrogen phosphate (KSCN doped

KDP) crystals were grown by Sankaranarayan Ramasamy (SR) technique. In general

KDP single crystals were grown by slow evaporation techniques but the crystals

grown by this method were much smaller in size. The KSCN doped KDP bulk single

crystal were also grown by slow cooling method. Potassium thiocyanate doped

potassium dihydrogen phosphate was synthesized and purified and the nucleation

parameters like solubility were determined. The solubility curves indicate high

solubility of KSCN doped KDP in water with a positive solubility temperature

gradient. Structure of the crystal were determined by XRD technique. The functional

groups in the grown crystal were confirmed by FT-IR analysis. The absorbance

ranges of the crystal were found by UV-visible spectrum. Microhardness values of

the crystal were also measured.

References:

[1] Book entitled “ Crystal growth processes and method” by Dr. P. Santhanaraghavan, and Dr.P.Ramasamy (1990), Kumbakonam

[2] Engineering physics by Dr.P.Mani,Dhanam publications, june 2005.

Load (gm)

Vicker’s microhardness

Hv(Kg/mm2)

109

[3]”The growth of single crystals” by R.A.Laudise, Eaglewood cliffs,1970.

[4]”Crystal growth process” by J.C.Brice, Halsted press, 1986.

[5]Center of crystal growth, SSN college of engineering, SSN Nagar, Kalavakkam

603110,India.

[6] Guohui Li, Xue Liping, Genbo Su, Xinxin Zhuang, Zhengdong Li, Youping He,

Journal of Crystal Growth, 274 (2005) 555-562.

[7] S. Balamurugan, P. Ramasamy Spectrochimica Acta Part A 71 (2009) 1979-

1983.

[8]A.P.voronov,Yu.T.Vyday,V.I.Salo,V.M.Puzikov,S.I.Bondarenko Radiation

measurements 42 (2007) 553-556.

[9] P.V. Dhanaraj, N.P Rajesh, C.K Mahadevan, G. Bhagavanarayana, Physica B

404 (2009) 2503-2508.

[10] Yusuke Asakuma,Shingo TAKEDA, kouji Maeda,Keisuke Fkui Applied

surface science 255 (2009) 4140-4144.

[11] Y. Enqvist, J. Partanen, M. Louhi-kultanen, J. Kallas, Chemical Engineering

Research and Design, 81 (2003) 1354-1362.

[12]Hartman. P, Structure and morphology in crystal growth.

[13]Genesa Moorthy.S, Joseph kumar. F, Subramaniyan, C, and Ramasamy .P

Structure of NLO Material.

[14]X-ray powder Diffraction (XRD) by Barbara L Dutrow, Louisiana State

university,Christine M. Clark, Easterrn Michigan university

[15]Material science and process by R.S.Khurmi and R.S.Sedha (1987).

110

Structural and Optical Studies of Wolframite Metal Tungstates (M2+ Wo4;

M=Co & Ni Synthesizes via Sonochemical Precipitation Technique

A. Sampathu1, K. Ravichandran1*

1Department of Nuclear Physics, University of Madras, Chennai, Tamilnadu, India

Corresponding Author Email: aspsampathu@yahoo.co.in

Abstract

Ni and Co doped metal tugstates (WO4) were synthesised by simple and cost

effective sonochemical method. XRD results showed the well crystalline nature with

monoclinic structure of Ni and Co doped WO4. From HRSEM micrograph, it is seen

that the nanocube morphology of the synthesised samples with less agglomeration.

The optical band gap has been found by the Tauc’s plot for the both samples, is 2.8

eV. It is clearly shows that the there is no variation in bandgap with doping of Ni and

Co in WO4. From the PL analysis it is conclude that the NiWO4 have possess the

excellent optical features over CoWO4 . NiWO4 is a great candidate for

optoelectronic applications.

Keywords: Metal tungstates, Nanocube, Bandgap, WO4.

1.0. INTRODUCTION

Recently, ternary oxide semiconductors that are M2+WO4 with the wolframite

crystal structure have been received much attention due to their technological

properties such as higher values of thermal stability, refractive indexes,

ferroelasticity, ionic conductivity and X-ray absorption coefficients [1-3]. Because of

its intriguing luminescence and structure properties, the metal tungstate is an

attractive material for photonics and photoelectronics. In these applications it is

important to study their optical band gap very accurately. However, earlier reports

show wide dispersion in the band gap and there was no agreement has been

observed. Till date wolframite structured metal tungstates of CdWO4, ZnWO4,

NiWO4, CoWO4 and MnWO4 are known for their wide applications in conventional

111

catalysis, or as scintillator material, in photoluminescence, optical fibres and as

materials in microwave technology [4–8]. Besides the above, the metal tungstates

were used as photocatalyst for removal of various organic pollutants from the water.

As a p-type semiconductor, CoWO4 has been widely investigated for optical devices

and photoluminescence materials [9]. It is well known that optical behaviour is

particle size dependent, therefore it should controlled through typical synthetic

conditions. According to the earlier reports many methods have been reported

including conventional ceramic method, sol-gel, hydrothermal and precipitation

technique. Among them chemical precipitation method is most widely used due to

their adequate synthetic conditions and cost effective for large scale production.

From the earlier reports it can be understandable that, in addition to the host

material, the dopant also play a vital role for luminescence efficiency. However, the

energy transfer and typical electronic transition and site symmetry of the host

material is still not clear and it needs further investigations.

In this present study we are interested to investigate the optical band gap and

luminescent characteristic NiWO4 and CoWO4 nanostructure. The optical response

of CoWO4 and NiWO4 was studied. The origin of characteristic band gap variation

and their luminescence were discussed.

2.0. Experimental

2.1. Synthesis of NiWO4 and CoWO4

Cobalt acetate (Co2+CH3COO-) and nickel acetate (Ni2+CH3COO-) are dissolved

in deionized water separately under sonication path for 15min.The pre-prepared

disodium tungstates (Na2WO4) solution were dropped in to above precursor solution

followed by sonication for 1h. After that stirring continued for 4h and followed the

aging for 12h. As obtained precipitates were washed well through the centrifugation

with DI water, ethanol and acetone several times and dried at room temperature

.Final products were calicined at 500°c for 4 h. Further, the synthesised powders

were investigated by X-ray diffraction analysis (XRD), High Resolution Scanning

112

Electron Microscope (HRSEM), UV-Vis spectroscopy and Photoluminescence

studies.

3.0. Result and discussion

3.1. X-Ray diffraction analysis

The structural properties were observed by XRD. From the Fig.1, it is seen that

prepared samples of diffraction peaks are assigned well to the wolframite like

monoclinic crystal structure. The lattice parameters of the metal tungstate’s are

found and tabulated in Table.1. Observed lattice parameters are well matched with

the Joint Committee on Powder Diffraction Standards (JCPDS); card #72-0480 and

#15-0867 for NiWO4 and CoWO4respectively. There is no additional peaks were

found in the XRD pattern. The average crystallite size was estimated from the XRD

peaks using Scherer Equation (1).

Where β is the full width half-maximum and λ is the wavelength of the X-ray.

The measured d values are in the 50 nm for CoWO4 and 80nm for NiWO4. These

values are fairly agreed with the FESEM. It is seen that from the Fig 1(b) the lattice

parameters little bit alter by doping of Ni and Co due to lattice distortion between

dopants and metal tungstate.

Table l. Calculated lattice parameters and Crystallite size

Lattice parameters ( )

Samples a b c

Crystallite

Size

(nm)

CoWO4 4.949 5.680 4.686 50

NiWO4 4.73 5.70 4.950 80

113

Fig 1. (a) XRD pattern of the CoWO4 and NiWO4. (b) Lattice parameters

variation with doping of CoWO4 and NiWO4.

3.2. HRSEM Analysis

The surface morphology of the NiWO4 and CoWO4 nanostructure was

analysed using HRSEM. Captured HRSEM images of the samples calcined at 500

°C for 4 h are shown in Fig.2(a-d). It can be seen that the particles are in present in

the shape of round edged cubical morphology with uniform distribution. When

compared to CoWO4, the NiWO4 nanoparticles have shown well resolved

morphology with less agglomeration. This is due to the strong crystalline features of

the material. Observed average particle sizes are in the range of 40-55 and 50-79 nm

for CoWO4 and NiWO4 respectively. This concludes that, with respect the

experimental technique and synthetic conditions it is possible to tune the

morphology. By tuning the morphology of the material there is possible to change

their optical and luminescent features which are necessary for opto-electronic

devices applications.

(a) (b)

114

Fig 2. HRSEM Micrograph

3.3. UV-Vis Spectra Analysis

The optical absorption spectra of NiWO4 and

CoWO4wolframite heat treated at 500 °C is illustrated

in Fig. 3. Broad UV absorption maximum at around

270-300 nm, were observed for both the tungstate

sample which confirms the unique optical behaviour of

the material and it is associated to the direct charge

transfer between ligand and metal within the (WO42-)

groups [10&12]. It can be seen that the strong UV

absorption edge with extended tail to higher wavelength in the UV-Vis spectra

represents the presence of localized energy bands.In the excited state of the (WO42-)

groups, the hole (on the oxygen) and the electron (on the tungsten) remain together

a b

c d

Fig 3

115

as an exciton because of their strong interactions [11]. Further absorption peaks in

the visible region are exhibited by NiWO4 which could be due to a charge transfer

transition in which an oxygen 2p electron goes into one of the empty tungsten 5d

orbital [11&12]. Similarly, for CoWO4the absorption band appeared at above 500

nm belongs to the d-d transition of octahedrally coordinated Co2+ ions in the CoWO4

nanostructure [13].With the strong UV absorption generally localized inter-atomic

excitation was observed at visible region and which is mainly due to d-d transition

on Co2+ [13].

Optical band gap of the prepared samples have been calculated by Tauc’s plot

using absorption as well as reflectance spectra from the following relation,

αhν = A(hν-Eg)n (2)

where in equation (2) α is the absorption coefficient, h is the Plank’s constant, v is

the photon energy, Eg is the band gap energy and n is a transition coefficient which is

1/2 and 2 for allowed direct transitions and indirect transitions respectively. Figure

3.4 represents the tauc plots of as prepared NiWO4 and CoWO4 nanostructure. The

linear extrapolation of the plot at α=0 corresponds to the energy band gaps of the

samples. Interestingly, both the material has shown the almost same optical energy

gaps as well which confirms the well quality

crystalline features of the material.

The estimated Eg value is ~2.8 eV as

shown in Fig 4 and which is in good

agreement with the earlier reports. The

observed band gap energy for NiWO4 is

slightly lower than the Rosiyah Yahya el al

and Tiziano Montini report [11&12].

Fig: 4 Tauc’s plot of CoWo4 and NiWo4

116

3.4 Photoluminescence Studies

Figure 3.5 shows the PL spectra of NiWO4 and CoWO4cubical nanostructure

annealed at 500 °C for the excitation of 220 nm at room temperature. The broad blue

emission was observed at around 420-455 nm without any hump or shoulder. This is

corresponds to the radiative transition of [WO4]2- tetrahedrons. The intrinsic

luminescence is caused by the annihilation of a self-trapped exciton, which formed

excited [WO6]6- complex. This can be excited either in the excitonic absorption band

or in the recombination process due to wolframite-structured products [14].

Although, there is no change in the emission band position due to the Ni2+ or

Co2+cations. However the relative PL intensity has been decreased drastically for

CoWO4. In general, the synthetic conditions, crystallinity and morphology of the

materials are strongly influences on the luminescence [15-19]. Therefore it is

important to control the particle size as well as morphology in order to increase the

luminescent efficiency. At 500 °C calcination there is low intense emission was

observed due to the less crystalline and aggregated surface morphology in the

CoWO4. In the case of NiWO4 the well crystalline nanocubes are present and thus

increase the PL intensity significantly. This is associated to the formation of good

quality crystalline NiWO4 with well-defined

nano cubical morphology with less

aggregation. Thus enhance the PL intensity

of the NiWO4 nanostructure than the

CoWO4. From the PL analysis it is conclude

that the NiWO4 have possess the excellent

optical features over CoWO4. It can be the

potential candidate for future optical devices

applications.

Fig. 5 photoluminance spectrum of

CoWo4 and NiWo4

117

4.Conclusion

Cowo4 and NiWo4 were successfully synthesised by sonochemical

precipitation technique. The XRD pattern revealed monoclinic phase and no

secondary peaks were conformed. The Clear morphology of nanocubes with round

edge crystals are observed from the High resolution scaning electron microscopy.

UV visible spectrum showed the absorption in the UV region. The band gap energy

were found by Tauc’s plot for as prepared Cowo4 and NiWo4. The strong UV-

absorption with extended tail in the UV-Vis spectra for both the tungstates

demonstrates the excellent optical behaviour of the wolframite nickel and cobalt

tungstates nanostructures. At 220 nm excitation wavelength, the strong PL emission

peak was centred at 420-455 nm regions for both the samples. In comparison to

CoWO4, the relative intensity of the emission band of NiWO4 nanocubes is

increased. This is due to the good quality and well crystalline natures of the NiWO4,

it leads to increase in luminescent intensity with the desired optical features.Ni

doped Wo4 nanostructure synthesised by sonochemical method highly appealing

material for optoelectronic devices.

References

1. Rajagopal S., Nataraj D., Khyzhun O. Yu., YahiaDjaoued, Robichaud J.,

Mangalaraj D.,Hydrothermal synthesis and electronic properties of FeWO4 and

CoWO4 Nanostructures, Journal of Alloys and Compounds,2010, Vol. 493, pp.

340–345.

2. Rajagopal S., Bekenev V.L., Nataraj D.,Mangalara jD.,Khyzhun O. Yu.,

Electronic structure of FeWO4 and CoWO4tungstates: First-principles FP-LAPW

calculations and X-ray spectroscopy studies, Journal of Alloys and Compounds,

2010, Vol. 496, pp. 340–345.

3. Scott H.P., Williams Q., and Knittle E., Ultralow compressibility silicate without

highly coordinated silicon, Phys. Rev. Lett., 2002, Vol. 88, pp.015506-015509.

4. Meddar L., Josse M., Deniard P., La C., Andre G., Damay F., Petricek V., Jobic

S., Whangbo M.-H., Maglione M., Payen C., Effect of nonmagnetic substituents

118

Mg and Zn on the phase competition in the multiferroicantiferromagnet MnWO4,

Chem. Mater., 2009, Vol. 21, pp. 5203-5214.

5. Zhen L., Wang W.-S., Xu C.-Y., Shao W.-Z., Qin L.-C., A facile hyrothermal

route to large-scale synthesis of CoWO4nanorods, Mater. Lett., 2008, Vol. 62, pp.

1740-1742.

6. Kuzmin A., Purans J., Kalendarev R., Pailharey D., Mathey Y., XAS, XRD,

AFM and Raman studies of nickel tungstate electrochromic thin films

Electrochim. Acta, 2001, Vol. 46, pp. 2233-2236.

7. de Oliveira A.L.M., Ferreira J.M., Silva M.R.S., de Sousa S.C., Vieira F.T.G.,

Longo E., Souza A.G., and Santos I.M.G., Influence of the thermal treatment in

the crystallization of NiWO4 and ZnWO4 J. Therm. Anal. Calorim., 2009, Vol.

97, pp. 167-172.

8. YuS.-H., Antonietti M., Cölfen H., and Giersig M., Angew. Chem. Int. Ed. 2002,

Vol. 41, pp. 2356.

9. Irina Kärkkänen, MargusKodu, Tea Avarmaa, JelenaKozlova, Leonard Matisen,

Hugo Mändar,Agu Saar, V.Sammelselg, RaivoJaaniso,Sensitivity of CoWO4

Thin Films to CO, Procedia Engineering,2010, Vol. 5 pp. 160–163.

10. Fang Lei, Bing Yan, and Hao-Hong ChenSolid-state synthesis, characterization

and luminescent propertiesof Eu3+-doped gadolinium tungstate and molybdate

phosphors:Gd(2-x)MO6:Eux3+ (M =W, Mo), Journal of Solid State Chemistry,

2008, Vol. 181, pp. 2845–2851.

11. SitiMurni M Zawawi., RosiyahYahya., Aziz Hassan., H N Mahmud.,

Mohammad Noh Daud., Structural and optical characterization of metal

tungstates (MAWO4; M=Ni, Ba,Bi) synthesized by a sucrose-templated method,

Chemistry Central Journal, 2013, Vol. 7, pp. 80.

12. TizianoMontini, ValentinaGombac, Abdul Hameed, Laura Felisari,

GianpieroAdami and Paolo Fornasiero, Synthesis, characterization and

photocatalytic performance of transitionmetal tungstates,Chemical Physics

Letters, 2010, Vol. 498 pp. 113–119.

119

13. Zuwei Song, Junfeng Ma, Huyuan Sun, Wei Wang,Yong Sun, Lijuan Sun,

Zhengsen Liu and Chang GaoSynthesis of NiWO4nano-particles in low-

temperaturemolten salt medium, Ceramics International, 2009, Vol. 35, pp.

2675–2678.

14. Naik S.J., and Salker A.V., Solid state studies on cobalt and copper

tungstatesnano materials, Solid State Sciences, 2010, V0l. 12, pp. 2065-2072.

15. Naik S. J., Uma Subramanian, Tangsali R. B.,and Salker A.V., Optical absorption

and photo luminescent studies of cerium-doped cobalt tungstate nanomaterials, J.

Phys. D: Appl. Phys., 2011, Vol. 44, pp. 115404 (7).

16. Thresiamma George, Sunny Joseph, AnuTresa Sunny and Suresh Mathew.,

Fascinating morphologies of lead tungstate nanostructures by chimiedouce

approach, J Nanopart Res, 2008, Vol. 10, pp. 567–575.

17. Yonggang Wang, Junfeng Ma, Jiantao Tao, Xiaoyi Zhu, Jun Zhou, Zhongqiang

Zhao, LijinXie and HuaTian., Low-temperature synthesis of CdWO4nanorods via

a hydrothermal method, Ceramics International, 2007, Vol. 33, pp. 1125–1128.

18. TitipunThongtem, AnukornPhuruangrat and SomchaiThongtem., Preparation and

characterization of nanocrystalline SrWO4 using cyclic microwave radiation,

Current Applied Physics, 2008, Vol. 8, pp. 189–197.

19. Jeong Ho Ryu, Jong-Won Yoon and Kwang Bo Shim., Blue luminescence of

nanocrystalline PbWO4 phosphor synthesized via a citrate complex route assisted

by microwave irradiation, Solid State Communications, 2005, Vol.133, pp. 657.

120

Effect of Fe on Cerium Oxide Nanoparticles

A.AArthi, P. Vijayashanthi, S. Shanmuga Sundari*

Department of Physics, PSGR Krishnammal College for Women, Coimbatore.

*Corresponding author mail id: shanmugi.s@gmail.com

ABSTRACT

Cerium oxide is one of the most important rare earth material and has been

widely investigated because of its multiple applications, such as a catalyst, an

electrolyte material of solid oxide fuel cells, a material of high refractive

index, and an insulating layer on silicon substrates. In the present work pure and 0.5

mol% of Fe doped cerium oxide nanoparticles have been prepared by co-

precipitation method at 300 K in which ammonia was added as precipitating agent

and FeCl3 as dopant. Crystalline nature and crystallite size were calculated from

XRD and it is found that it decreases after incorporation Fe in CeO2 lattice. The

absence of secondary peaks confirms a complete solid solution of Fe and CeO2,

Direct and indirect band gap were calculated from UV-Vis spectra. Surface

morphology was studied by SEM. Magnetic characteristics were analyzed from

VSM .

1. INTRODUCTION:

Ceria is a fluorite-structured rare earth oxide. Cerium oxide is a cheap and

widely used rare earth material. Cerium oxide (ceria) is an important material for the

application to practically used polishing agents [1], sunscreens [2], solid electrolytes

[3], and automotive exhaust catalysts [4]. Recently, ultrafine nano particles have

attracted much attention due to the physical and chemical properties that are

significantly different from those of bulk materials. Many studies have been carried

out to obtain ceria single nano particles smaller than 10 nm [5]. As reported, various

techniques based on the chemical wetness routes have been extensively used to

prepare CeO2 nano particles, such as hydrothermal [6,7], reverse micelles [8], sono

chemical [9], pyrolysis [10] and homogeneous precipitation [11–15] . Cerium oxide

also has optical properties, high thermal stability and electrical conductivity and

diffusivity. For all these cases, nano structured CeO2 has attracted much attention

121

due to improvements in the redox properties, transport properties and surface to

volume ratio with respect to bulk materials [16]. The method described here is based

on a coprecipitation synthesis. Fabricating CeO2 nano particles by co precipitation

method is due to advantages of low cost, mild synthesis condition and easy scale-up.

Precipitation method is a kind of wet-chemical methods through which the grains

with small size. The grain size of the products depends on the solubility of

precipitate, i.e the smaller the precipitate solubility, the smaller the grain size. In the

present work ceria and 1 mol of Fe doped paricles were prepared by co

precipitation method and the prepared samples were characterized by X-ray

diffraction (XRD), Scanning electron microscopy (SEM), Fourier transformation

infrared spectroscopy (FT-IR), ultraviolet and visible spectroscopy (UV–vis),

photoluminescence spectrum (PL), vibrating sample magnetometer(VSM).

2. EXPERIMENTAL TECHNIQUES:

CeO2 nano particle were synthesized using by coprecipitation method. 50ml

of Distilled water was used as solvent and the chemicals used were analytical reagent

grade. Cerium nitrate hexahydrate is used as starting material. Cerium nitrate

hexahydrate was dissolved in distilled water, in a clear solution after 1hr the dopent

1 mol % FeCl3 was added. The clear solutions suddenly change into transparent

brown solution. 25ml of ammonia was added to the solution as a precipitating agent.

Brown precipitates was formed all of a sudden and stirred for 8 hrs continuously to

get a clear solution. The solution was centrifuged for 45 min and washed with water

and ethanol subsequently. The collected particles were dried at 100 oC for hours.

The prepared particles were analysed using XRD, FTIR, SEM, UV-vis, PL and VSM

3. RESULT AND DISCUSSION:

3.1.XRD ANALYSIS:

Figure 1 show the X-ray diffraction patterns of pure (S1) and 1 mol. % of Fe-

doped CeO2 (1M). It reveals that there are several crystalline peaks at 2θ values of

28.22˚, 33.00˚, 47.17˚, 56.07˚, 69.02˚, 77.01˚ and 88.23˚. The corresponding hkl

planes of [111], [200], [220], [311], [400], [331] and [422]. All diffraction patterns

can be indexed as CeO2 with cubic fluorite structure in the JCPDS card no. 34-0394.

122

The XRD patterns of the peak were broad, suggesting the relatively small particles.

From the X-ray diffraction pattern of the samples, the average crystallite size of the

sample can be estimated by the Scherrer equation,

D = Kλ/β cosθ (1)

where D is the crystallite size of the sample, K is the Scherrer shape factor, here

K=0.9; λ is the wavelength of X-ray CuKα (λ =0.154nm), β is the full-width at half-

maximum (FWHM) in radian and θ is the Bragg angle of the X-ray diffraction peak.

Table .1. shows the lattice parameter and crystalline size of S1 and 1M nanoparticles.

Fig.1.X-ray diffraction patterns of S1and 1M nanoparticles

Table.1Particle size and lattice constant of S1 and 1 M

Sample Particle size D in (nm) Lattice constant a in Å

S1 7-7.4 5.4

1M 4.4-6.6 5.4

3.2. FT-IR ANALYSIS:

Fig.2. presents the FT-IR spectrum of S1 and 1M nanoparticles in the range

from 4000 cm-1to 400 cm-1 and the peak assignments are listed in Table 2.

123

Table.2 FTIR peak assignments of S1 and 1 M

S1 band

position

1M-

band

position

Band assignment Functional group

3447 3412 O-H stretch,H-bonded alcohols

2884 C-H stretch Alkanes

2803 H-C=O: C-H stretch Aldehydes

2253 -C≡C-strech Alkynes

1737 C=O strech carbonyls (general)

1542 N-O asymmetric stretch nitro compounds

1401 C-C stretch Aromatics

1362 C-H rock Alkanes

1333 N-O symmetric stretch Nitro compounds

1216 C-O stretch alcohols, Carboxylic

acids,esters,

833, 634 C-CI strech Alkyl halides

Fig.2. FT-IR spectrum of S1 and 1M nanoparticle

124

3.5. SCANNING ELECTRON MICROSCOPE

The SEM images of the pure and doped (1mol %) CeO2 nanoparticles are

shown in the Fig.3. The undoped and FeCl3 doped CeO2 nanoparticles having

uniform spherical like structure. The e doped particles are smaller than pure one

Fig.3.SEM Image of pure (S1) and FeCl3(1mol %) doped CeO2 nanoparticle

3.4. ULTRA-VOILET VISIBLE SPECTRAL ANAYSIS:

Fig.4.shows the UV Visible absorption spectrum of S1 and 1M nano particles in the

rang 200 nm to 2200 nm. The absorption bands are corresponds to electron

excitation from the valence band to conduction band, and be can be used to

determine the nature and value of the optical band gap. Optical band gap is obtained

using the following equations.

α(hν) = A(hν –Eg)m/2 (2)

where, A is a constant and Eg is the band gap of the material and exponent n depends

on the type of transition. For direct allowed transition n = 2, indirect allowed

transition n=1/2. To measure the energy band gap value from the absorption spectra,

a graph (αhγ)2 versus (hγ) is plotted and the values are listed in Table 3.

125

Fig.4 UV-vis spectra of S1 and 1M nanoparticle.

Table.3. Band gap values for S1 and 1 M

SAMPLE DIRECT BANDGAP INDIRECT

BANDGAP

S1 2.84 eV 2.65eV

1M 1.61 eV 1.44 eV

3.5. PHOTOLUMINOSCENCE ANALYSIS

The PL spectrum of the S1 and 1M nanoparticles are shown in the Fig.5. The

intensity of the peak

decreased after the

addition of Fe and blue

shift was observed which

indicates the reduction in

particle size.

Fig.5. PL spectrum of S1 and 1M nanoparticles

126

4. CONCLUSION:

Ceria and Fe doped cerium oxide nanoparticles were synthesized by co-

precipitation method. The synthesized nanoparticles are subjected to X-ray

diffraction technique to analyse the structure. The FT-IR spectrum of the sample is

recorded and the characteristic absorption bands are observed. Bandgap energy

calculated from the uv-vis. SEM analysis show regular spherical like particles.

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[15] N. Uekawa, M. Ueta, Y.J. Wu, K. Kakegawa, Chem. Lett. 2002; 854.

[16] C.-W. Sun, H. Li, H.-R. Zhang, Z.-X. Wang, L.-Q. Chen, Nanotechnology 16

(2005) 1454.

127

GROWTH AND CHARACTERIZATIONS OF (TRI) GLYCINE BARIUM

CHLORIDE SINGLE CRYSTAL FOR OPTOELECTRONICS AND

PHOTONICS APPLICATIONS

S. Chennakrishnan1, D. Sivavishnu2, T. Kubendiran2, S.M. Ravi Kumar2* 1 Department of Physics, Idhaya Arts & Science College for women, Tiruvannamalai

606 705 2 PG & Research Department of Physics, Government Arts College, Tiruvannamalai

606 603, *Corresponding author: smravi78@rediffmail.com

ABSTRACT

The single crystal of (tri) glycine barium chloride, a semiorganic crystal has been

grown from an aqueous solution by slow evaporation technique at room

temperature. Glycine and barium chloride were used in molar ratio of 3:1 for

synthesis. Good optical quality single crystal of size 18×10×5 mm3 was harvested

in a period of 35 days at pH value 5. The lattice parameters have been measured by

single crystal XRD study. Fourier transform infrared (FTIR) spectroscopy study

confirmed the presence of functional groups in grown crystal. The thermal

behavior of the crystal was investigated by TG-DTA analysis, which reveals that

crystal has thermally stable up to 169ºC. Non-linear optical property of the grown

crystal has been confirmed using the Kurtz and Perry powder technique and result

was compared with KDP.

1.Introduction

Non-linear optics is an emerging field as it extends the usefulness of lasers by

increasing the original frequency of incident radiation. Non-linear optical (NLO)

materials are capable of producing higher values of the original frequency and,

hence, this phenomenon can find applications in optical modulation, fiber optic

communication, photonics and opto- electronics [1-3]. In recent years, many

researchers have tried to find varieties of NLO materials for laser applications. The

complexes of organic material with inorganic acids and salts are promising materials

for second harmonic generation (SHG) as they tend to combine the features of

organic with that of inorganic materials. In general, organic materials are showing a

good efficiency for SHG but poor mechanical and thermal properties. It is difficult to

128

grow large size crystals with good optical quality of these materials for device

applications [4]. Most of the amino acids and their complexes are the family of

organic and semiorganic non-linear optical (NLO) materials that have potential

applications in second harmonic generation (SHG), optical storage, optical

communication, photonics, electro-optic modulation, optical parametric amplifiers,

and optical image processing [5-10].

Also amino acids are interesting materials for NLO applications due to the

fact that the carboxylic acid group donates its proton to the amino group to form a

salt of the structure CH3CHCOO-NH3+. Thus in solid state, amino acid exists as

dipolar ion in which carboxyl group is present as carboxylate ion. Due to this dipolar

nature, amino acids have promising physical properties which make them ideal

candidate for NLO applications. Recently, the amino acid group materials were

mixed with organic or inorganic salts in order to improve their chemical stability,

laser damage threshold, thermal, physical properties and linear and non linear optical

properties.

Glycine (NH2-CH2-COOH) is the simplest amino acid. Unlike other amino

acids, it has as symmetric carbon atom and is optically inactive. It has three

polymeric crystalline forms α, β and γ, in which α-glycine is commonly available.

Glycine mixed with metal chlorides such as zinc chloride [11], calcium chloride

[12], potassium chloride [13], sodium chloride [14], lithium chloride [15] have been

reported in the recent years. Interest have been centered on semiorganic crystal

which have the combined properties of both inorganic and organic crystals like high

damage threshold, wide transparency range, less deliquescence, higher mechanical

strength and chemical stability which make them suitable for device fabrication [16].

The advantage of including semiorganic material is to grow from aqueous solution

and forms a large three dimensional crystal of excellent physico-chemical properties.

Hence, it is necessary to synthesize and grow novel semiorganic crystals which have

positive aspects of both organic and inorganic.

In this present investigation we report bulk growth (tri) glycine barium chloride

crystal by solution growth technique. The grown crystals were characterized using

single crystal XRD and powder X-ray diffraction, fourier transform infrared (FT-IR)

analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and

129

UV-vis spectroscopy. Optical constants like refractive index, reflectance, extinction

coefficient and electric susceptibility and also dielectric constant, dielectric loss and

photoconducting nature have been determined for the first time.

2. Experimental Procedure

2.1 Synthesis

The compound (tri) glycine barium chloride was synthesized by reacting

glycine (Merck, GR grade) barium chloride (Merck, GR grade) with stoichiometric

ratio of 3:1. A necessary quantity of glycine is taken in a beaker and dissolved in

double distilled water at room temperature until it attains a saturated condition. After

preparing saturated solution of glycine, the proportionate amount of barium chloride

was added with continuous well stirring for 4 hours to bring a homogenous mixture

of solution. The (tri) glycine barium chloride was synthesized on the following

chemical reaction.

3(NH2-CH2-COOH) +BaCl2 Ba(NH2-CH2-COO)3Cl

2.2 Crystal growth

Recrystallization was carried out to eliminate any impurities in the (tri) glycine

barium chloride crystal. The recrystallized salt was used for the preparation of

saturated solution. The saturated solution was filtered using whattman filter paper to

remove impurities. This super saturated solution was tightly covered with

polyethylene sheet, to keep out dust before it was allowed to evaporate at room

temperature. After 15 to 20 days good quality seed crystals were obtained. The good

quality and defect free seed crystal was selected for bulk growth. The (tri) glycine

barium chloride crystal of average

dimension 18×10×5 mm3 has been

harvested in the period of 25 to 35 days

and the grown crystals are highly

transparent. As grown crystal of (tri)

glycine barium chloride is shown in

Figure 1.

Figure 1 As grown crystal of (tri) glycine barium chloride

130

3432

.73

3062

.56

2981

.59

2898

.36

2698

.10

2589

.49

2039

.15

1571

.73

1478

.33

1404

.45

1330

.91

1116

.77

1031

.78

896.

38

668.

43

100015002000250030003500Wavenumber cm-1

9394

9596

9798

9910

0Tr

ansm

ittan

ce [%

]

3 Results and discussion

3.1 Single crystal X-ray diffraction

Single crystal X-ray diffraction analysis of (tri) glycine barium chloride was

recorded using ENRAF NONIUS CAD-4 diffractometer. The calculated lattice

parameters are a=8.281Ǻ, b=9.410 Ǻ, c=14.898 Ǻ, α=β=γ=90º and volume V=

1160.177 Ǻ3 which confirm the orthorhombic crystal system with non-

centrosymmetric space group pbcn.

3.2 Fourier Transform Infrared (FTIR) spectroscopy study

The infrared spectral analysis is effectively used to understand the chemical

bonding and provides information about molecular structure of the synthesized

compound. Crushed powder of (tri) glycine barium chloride was pelletized using

KBr. The spectrum was recorded using a Thermo Nicolet V-200 FTIR Spectrometer

in the range 400-4000 cm-1 wavenumber region. The FTIR spectrum of (tri) glycine

barium chloride is shown in Figure 2. The peaks around 3432 cm-1 is due to NH

asymmetric stretching. The peaks obtained at 2981, 2698 cm-1 for CH stretching.

The peaks of IR spectrum at 2689, 2589 cm-1 is due to NH3+ stretching vibration.

The peaks around 1571 cm-1 is due to NH3+ deformation. A peak at 1478 cm-1 has

been assigned to NH2 deformation vibration. A peak 1404 cm-1 is due to COO-

symmetric stretching. The peak at 1330 cm-1 is due to C-N-H symmetric bending.

The peak around 1116 cm-1 is due to CH2 rocking. A peak at 1031 cm-1 for C-C-N C

symmetric stretching. The peaks at 896 and 668 cm-1 are due to C-CN stretching and

C-Cl stretching respectively.

The band assignments for

corresponding wavenumber

of FTIR spectrum of (tri)

glycine barium chloride are

presented in Table 1.

Figure 2. The FTIR spectrum of (tri) glycine barium chloride

131

200 400 600 800 1000

0

20

40

60

80

100

Tran

smitt

ance

%

Wavelength (nm)

Table 1. Band assignments of FTIR spectrum of (tri) glycine barium

chloride.

Wavenumber cm-1 Assgnments 3432 NH asymmetric 3062 NH2 stretching

2981, 2898 CH stretching 2698, 2589 NH3

+ stretching 1571 NH+

3 deformation 1478 NH2 deformation 1404 COO- symmetric 1330 C-N-H symmetric 1116 CH2 rocking 1031 C-C-N C symmetric 896 C-CN stretching 668 C-Cl stretching

3.3 Optical transmission study

The optical transmission spectrum was recorded using DOUBLE BEAM UV-

Vis Spectrophotometer:2202 in the region 200-1000 nm and the optical transmission

spectrum of

(tri) glycine barium chloride is shown in Figure 3. The transmission is maximum in

the entire visible region and infrared region. In (tri) glycine barium chloride, the UV

transparency cut-off wavelength lies at 234 nm and the percentage of transmission is

high in the entire visible region from 234 nm to 1000 nm. The absence of absorption

in the entire visible region makes the triglycine barium chloride crystal as a potential

candidate for second harmonic generation and various applications [18].

Figure 3. Optical transmission

spectrum of (tri) glycine barium

chloride crystal

3.4 TGA/DTA annalysis

Thermal properties of the

material was studied by

Thermogravimetric (TGA) and Differential

Thermal Analysis (DTA) using STA 409 C instrument between the temperature 50

132

and 800 ºC at a heating rate of 20 ºC per min in the nitrogen atmosphere. (Tri)

glycine barium chloride sample weighing 4.237 mg was taken for the measurement.

TGA and DTA curve of (tri) glycine barium chloride crystal is shown in the Figure

4. DTA curve shows a sharp endothermic peak at 169.3 ºC which corresponds to the

melting point of the compound. Hence the thermal stability of (tri) glycine barium

chloride is around 169 ºC. The absence of water of crystallization in the molecular

structure is indicated by the absence of weight loss around 100 ºC. The

material decomposes at 321.8 ºC, which is represented by the sudden loss of the

mass. The weight loss is due to the decomposition of glycine. Above 321.8 ºC, the

material undergoes irreversible endothermic transition around at 500 ºC. From the

TG curve, the mass loss takes place after the temperature of 169.3 ºC. The mass lost

from 169 ºC to 321 ºC is found to be 43% which is the sublimation of the Cl. There

is further mass loss of 7% occuring in the temperature limit of 321-500 ºC which

involve the evolution of NH3. The actual residual amount of mass is 50% which

may be considered to be the compound of barium. From the above analysis, the

melting point of the (tri) glycine barium chloride is 169 ºC which is higher than the

other semiorganic materials like bis-glycine hydrogen chloride (146.8 ºC ), tetra

glycine barium chloride (160 ºC), α-glycine sulpho-nitrate (143 ºC) [22-24].

T e m p C e l8 0 0 .07 0 0 .06 0 0 .05 0 0 .04 0 0 .03 0 0 .02 0 0 .010 0 .0

DTA

uV

4 5 .0 0

4 0 .0 0

3 5 .0 0

3 0 .0 0

2 5 .0 0

2 0 .0 0

15 .0 0

10 .0 0

5 .0 0

0 .0 0

-5 .0 0

-10 .0 0

TG %

10 0 .0

9 0 .0

8 0 .0

7 0 .0

6 0 .0

5 0 .0

4 0 .0

3 0 .0

2 0 .0

10 .0

0 .0

16 9 .3Ce l5 .3 6uV 321 .8Ce l

4 .3 3uV

5 .3%

43 .0%

Figure 4. TG/DTA curve of (tri) glycine barium chloride crysta

133

3.5 Kurtz powder SHG test

In order to confirm the non-linear optical property of powdered sample of

(tri) glycine barium chloride was subjected to KURTZ and PERRY techniques,

which remains powerful tool for initial screening of materials for SHG efficiency

[19]. A Q-switched Nd: YAG laser emitting 1.06µm with power density up to 1

GW/cm2 was used as a source of illuminating the powder sample. The sample was

prepared by sandwiching the graded crystalline powder with average particle size of

about 90µm between two glass slides using copper spices of 0.4 mm thickness. A

laser was produced a continuous laser pulses repetition rate of 10Hz. The

experimental setup uses a mirror and 50/50 beam splitter. Here well known NLO

crystal KDP is taken as a reference material.

The fundamental beam was splitted into two beams by the beam splitter (BS);

one of them was used to illuminate the powder under study and the other constituted

the reference beam of power Pω. Half-wave plate (HW) placed between two parallel

polarizers (P) and was used to pump the beam power. The input power was fixed at

0.68 J and the output power was measured as 4.4 mJ, which was compared to output

8.8 mJ of standard KDP. The diffusion of bright green radiation of wave

lengthλ=532 nm (P2ω) by the sample confirms second harmonic generation (SHG).

The powder SHG efficiency of (tri) glycine barium chloride crystal was about 0.5

times of KDP. The good second harmonic generation efficiency indicates that the

(tri) glycine barium chloride crystals can be used as a suitable material for non-linear

optical devices.

4.0 Conclusion

Well developed good quality transparent crystal of (tri) glycine barium chloride

was grown successfully by slow evaporation technique. Unit cell constants and

crystal system were determined by single crystal X- ray diffraction technique

confirmed the identity of the synthesised material. Powder XRD shows good

crystallinity of the grown crystal. The various functional groups presence in the

grown crystal was identified by FTIR study. The UV cut off wavelength of (tri)

glycine barium chloride crystal is found to be around 234 nm, which reveals grown

crystal is potential candidate for NLO applications. The optical bandgap (Eg),

134

absorption coefficient (α), extinction coefficient (K) was also calculated from UV

spectrum. The thermal analysis shows the melting point of grown sample is 169 ºC.

The powder SHG analysis shows that the efficiency of crystal is 0.5 times than that

of KDP.

REFERENCE

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Hydrogen bonded nonlinear optical gamma-glycine: Crystal growth and J.

Crystal Growth 280(2005) 581-586.

2. T apati Mallik, Tanusree Kar, Synthesis, growth and characterization of a new

nonlinear

optical crystal: l-arginine maleate dehydrate, Cryst.Res Technol. 40 (2005)

778-781.

3.Kandasamy, R. Siddeswaran, P. Murugakoothan, S.P. Kumar, R. Mohan,

Synthesis, Growth, and Characterization of l-Proline Cadmium Chloride

Monohydrate (l-PCCM) Crystals: A New Nonlinear Optical Material, Cryst.

Growth Des. 7 (2007) 183-186.

4.K. Ambujan, K. Rajarajan, S. Selvakumar, I. vetha potheher, G.P. Joseph, P.

Sgayaraj Growth, Optical, Dielectric and Fundamental Properties o NLO active

L-histidinium Perchlorate Single Crystals, J. Crystal.Growth 286 (2006) 440-444.

5.D. Eimerl, S. Velsko, L. Davis, F. Wang, G. Loiacona, G. Kennedy, Deuterated L-

arginine phosphate: a new efficient nonlinear crystal, IEEE Quantum Electron. 25

(1989) 179-193.

6.K. Meera, R. Muralidharan, R. Dhanasekaran, Prapun Manyum, P. Ramasamy,

Growth of nonlinear optical material: L-arginine hydrochloride and its

characterization, J. Cryst.Growth 263 (2004) 510-516.

7.M. Vimalan, A. Ramanand, P. Sagayaraj, Synthesis, growth and characterization of

l-alaninium oxalate - a novel organic NLO crystal, Cryst.Res. Technol. 42 (2007)

1091-1096.

8.K. Kirubavathi, K. Selvaraju, R. Valluvan, N. Vijayan, S. Kumararaman,

Synthesis, growth, structural, spectroscopic and optical studies of a new

semiorganic nonlinear optical crystal: l-Valine hydrochloride, Spectrochimica.

Acta part A 69 (2008) 1283-1286.

135

9.S.B. Monaco, L.E. Davis,S.P. Velsko, F.T. Wang, D. Eimerl, A.J. Zalik, Synthesis

and characterization of chemical analogs of L-arginine phosphate,

J.Cryst.Growth 85 (1987) 252-255.

10. C.Justin Raj, S. Dinakaran, S. Krishnan, B. Milton Boaz, R. Robert, S. Jerome

Das, Studies on optical, mechanical and transport properties of NLO active l-

alanine formate single crystal grown by modified Sankaranarayanan–Ramasamy

(SR) method, Optics Commun. 281 (2008) 2285-2290.

11. T. Balakrishnan and K. Ramamurthi, Growth, structural, optical, thermal and

mechanical properties of glycine zinc chloride single crystal, Materials

Letters,62 (2008)65-68.

12. M. Ayanar, J. Thomas Joseph Prakash, C. Muthamizhchelvan and S. Ponnusamy,

Journal of Physical Sciences,13 (2009) 235-244.

13. S. Palaniswamy and O.N. Balasundaram,Rasayan, Growth and characterization of

semi-organic nlo material: glycine potassium chloride (GPC), J.Chem,2 (2009)

28-33.

14. S. Palaniswamy and O.N. Balasundaram,Rasayan, Effect of ph on the growth and

Characterization of glycine sodium chloride (GSC) single crystal,J.Chem,1

(2008) 782-787.

15. R. Varatharajan and Suresh Sagadevan, Studies on the mechanical properties of

glycine lithium chloride NLO single crystal, International Journal of Physical

Sciences,8(39) (2013)1892-1897.

16. J. Qin, D. Liu, C. Dai, C.Chen, B. Wu, C.Yang, C.Zhan, Influence of the

molecular configuration on second-order nonlinear optical properties of

coordination compounds Coord.Chem.Rev 188 (1999) 23-34.

17. M.D. Aggarwal, J. Choi, W.S. Wang, K. Bhat, R.B. Lal, A.D. Shields, B.G. Penn,

D.V. Frazier, Solution growth of a novel nonlinear optical material: L-histidine

tetrafluoroborate, J.Cryst.Growth 204 (1999) 179-182.

18. R. Christian, solvents and solvent effects in organic chemistry, VCH, New York,

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Materials,

Journal of Applied Physics, Vol. 39(1968) 3798-3813.

136

Measurement of Natural Radioactivity and Assessment of Radiological Hazards

in Coastal sediments of Cuddalore Coast, Tamilnadu, India

K. Thillaivelavan1, N. Harikrishnan2, G. Senthilkumar3, R. Ravisankar2* 1Department of Physics, Periayar Arts College, Cuddalore 607 001, Tamilnadu,

India 2Post Graduate and Research Department of Physics, Government Arts College,

Thiruvanamalai 606603,Tamilnadu, India 3Department of Physics, University College of Engineering Arni, Arni 632317,

Tamilnadu, India

E-Mail: ravisankarphysics@gmail.com; Tel : +91-9443520534

Abstract

Natural and artificial radionuclide pollutants of the marine environment have

been recognized as a serious environmental concern. In the present work, the natural

radioactivity levels in beach sediment samples collected from Thazhankuda to

Rasapettai, of Cuddalore Coast, Tamilnadu have been determined using gamma ray

spectrometry. The activity concentration of 238U, 232Th, and 40K in sediment samples

was measured by NaI (Tl) detector. The average specific activities for 238U, 232Th

and 40K were found to be 7.202, 31.474 and 328.716 Bq kg-1 respectively.. The

average activity of 238U, 232Th and40K is lower when compared with worldwide

average value.The results have been compared with other radioactivity

measurements in different countries. The radiation hazard due to the total natural

radioactivity in the study area was estimated using radiation indices such as absorbed

dose rate (DR), annual effective dose equivalent (AEDE) and external hazard indices

(Hex) and they are compared with the international recommended values and safety

limits. The values of radiation hazard parameters are below the recommended

values. Therefore, coastal sediments are unlikely to pose radiological health risk to

the people living in nearby the study area.

Keywords: Natural Radioactivity, Sediment, Gamma Ray Spectrometry,

Radiological Hazards

137

1.0. Introduction

Naturally occurring radioactive materials generally contain terrestrial origin

radionuclides (primordial radionuclides), left over since the creation of the earth

(UNSCEAR, 1982). They are typically long lived with half lives of about hundreds

of millions of years. Gamma radiation emitted from natural sources (background

radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series and

their decay products, as well as 40K, which exist at trace levels in the earth’s crust.

The knowledge of the concentrations and distributions of these radionuclides are of

interest since it provides useful information in the monitoring of environmental

contamination by natural radioactivity.

The concentration of radionuclides in marine sediments can provide very

useful information on the source, transport mechanisms and environmental fate of

radionuclides. A considerable attention has been given, to allow the creation of

scientific database of the radiological baseline levels on the coastal region of the

study area using γ-ray spectrometry. Obtaining activity concentrations of natural

radionuclides are useful for radiation risk assessment. The baseline data can be used

to assess any changes in the radioactivity background level due to various activities

involving radioactive materials or any fallout in the near future. The measurement

will also help in the development of standards and guidelines for use.

Natural radioactivity measurements in coastal sediments in different parts of

the world were reported by many authors [Orgun et al ., (2007); Arogunjo et al.,

(2004); Saad andAl-Azmi, (2002); Uosif et al.,(2008); Alam et al.,(1999);

Ravisankar et al., (2014); Chandramohan et al., (2015)]. To our knowledge, there

seems to be no information about radioactivity level in and around Cuddalore coast,

Tamilnadu. In this study, the gamma radiation has been measured to determine

natural radioactivity of 238U, 232Th and 40K in coastal sediment samples from

Thazhankuda to Rasapettai, Cuddalore of East Coast of Tamilnadu.

2.0. Materials and methods

2.1. Sample collection and Preparation

Sediment samples were collected along the Bay of Bengal coastline, from

Thazhankuda to Rasapettai coast of Cuddalore Dist, Tamilnadu during pre-monsoon

138

condition. Table-1 represents the geographical latitude and longitude for the

sampling locations at the study area.

Table 1. Geographical latitude and longitude for the sampling locations of the

study area

S

No. Sample ID Area Name Longitude Latitude

1 CTZ Thazhamguda 11°45'58.9932"N 79°47'16.4652"E

2 CDP Devanampattnam 11°44'47.9724"N 79°47'0.3876"E

3 CSK Sonankuppam 11°43'26.6556"N 79°46'50.2968"E

4 CKI Kori 11°42'35.7084"N 79°46'40.2060"E

5 CRP Rasapettai 11°40'56.2692"N 79°46'17.5008"E

Sampling locations were

selected to cover the shore area

as uniformly as possible

Sediments were collected at a

depth of about 10 cm by a Grab

sampler. Each sample of about 2

kg was kept in a thick plastic

bag. The collected samples were

air dried at room temperature in

open air then brought to the

laboratory, where they were

dried for 12 hours in an oven at

105˚C to constant mass. Then

pebbles, leaves and other foreign

particles were removed. Sediment samples were sieved with a 250 micron mesh

laboratory test sieve. Samples were then stored for a period of 4 weeks to allow

radioactive equilibrium to be attained between 238U (226Ra) and 232Th (228Ra) and

their progenies. The sample location map is shown in Fig-1.

139

2.2. Gamma ray spectrometric analysis

Measurements of the activity concentrations of 238U, 232Th and 40K in Bq kg-1

dry weight of the collected samples were carried out with a counting time of 10,000

secs using gamma-ray spectrometry. A 3" x 3" NaI (Tl) detector was employed with

adequate lead shielding whichreduced the background by a factor of about 95%. The

concentrations of various radionuclides of interest were determined in Bq kg–1 using

the count spectra. The gamma ray photo peaks corresponding to 1.46 MeV (40K),

1.76 MeV (214Bi) and 2.614 MeV (208Tl) were considered in arriving at the activity

of 40K, 238U and 232Th in the samples. The detection limit of NaI(Tl) detector system

for 40K, 238U and 232Th are 8.50, 2.21 and 2.11 Bq kg–1 respectively for a counting

time of 10, 000 secs.

3.0. Results and Discussion

3.1. Activity concentrations of 238U, 232Th and 40K in the sediments

The activity concentrations of 238U, 232Th and 40K in the sediment samples are

given in Table-2. All values are given in Bq kg-1 of dry weight. The activities range

and mean values (in brackets) for 238U, 232Th and 40K are ≤ 2.21 - 19.82 (7.20), ≤

2.11 - 101.43 (31.47) and 292.75- 387.14 (328.71) Bq kg-1 respectively. The wide

variations of the activity concentration values are due to their presence in the marine

environment and their physical, chemical and geo chemical properties (Khatir et al.,

1998, El Mamoney et al., 2004). The results show that the mean activity of 238U and 40K is lower whereas 232Th is slightly higher than when compared with worldwide

average values (35 Bq kg−1 for 238U, 30Bq kg−1 for 232Th and 400 Bq kg−1 for 40K,)

(UNSCEAR, 2000). Table-3 lists the activity concentration of different parts of the

world. Fig-2 shows the variation of activity concentration at different sampling

locations.

Fig- 2. Variation of activity concentration (Bq kg-1) at different sampling

locations

140

Table 2

Activity concentration (Bq kg-1), Absorbed Gamma Dose Rate (DR), Annual

Effective Dose Rate (AEDR), and External Hazard index (Hex) in coastal

sediments

Activity Concentration

Bq Kg-1 S.

No

Sample

ID 238U 232Th 40K

Absorbed

Gamma

Dose Rate

(DR)

nGy h-1

Annual

Effective

Dose

equivalent

(AEDE)

External

Hazard

index

(Hex)

1 CTZ 9.56 13.21 292.75 24.638 0.030 0.138

2 CDP 19.82 101.43 319.26 83.424 0.102 0.512

3 CSK BDL 18.92 303.38 25.115 0.030 0.142

4 CKI BDL 21.71 341.05 28.371 0.034 0.161

5 CRP BDL BDL 387.14 18.541 0.022 0.095

Average 7.20 31.47 328.71 36.018 0.044 0.209

Table 3

Comparison of activity concentration of present work with other

countries

Activity concentration (Bqkg-1) S. No. Name of the Location

238U 232Th 40K References

1 Ezine region, Turkey 290 532 1160 Orgun et al., (2007)

2 Nigeria 16 24 35 Arogunjo et al., (2004)

Saudi Coastline 3 (Gulf of Aqaba)

11.4 22.5 641.1 Al-Trabulsy et al., (2011)

4 Turkey(Firtina River) 16-113 17-87 51-

1605 Kurnaz et al., (2007)

5 Bangladesh 19 37 458 Alam et al., (1999)

6 Cuddalore Dist, Tamilnadu, India 7.20 31.47 328.71 Present work

141

4.0. Evaluation of radiological hazard effects

4.1. Absorbed gamma dose rate (DR)

The greatest part of the gamma radiation comes from terrestrial radionuclides.

It is the first major step for evaluating the health risk and is expressed in gray (Gy).

The contribution of natural radionuclides to the absorbed dose rate in air (DR)

depends on the natural specific activity concentration of 238U, 232Th and 40K. The

conversion factors used to compute absorbed gamma dose rate (DR) in air per unit

activity concentration in Bq kg-1 (dry weight) corresponds to 0.462 nGy h-1 for 238U,

0.604 nGy h-1 for 232Th and 0.042 nGy h-1 for 40K.

DR (nGy h-1) = 0.462 AU+ 0.604 ATh + 0.042 AK------------------- (1)

Where, AU, ATh and AK represent the activity concentrations of 238U, 232Th

and 40K in Bq kg-1 respectively in the samples. Using the above equation DR had

been calculated and tabulated (Table-2).The absorbed dose rate values ranged

between 18.541 and 83.424, with a mean value of 36.018 nGy h-1. This mean value

is less than the world average absorbed dose rate value of 84 nGy h-1.This indicates

that the area monitored can be regarded as having normal dose level. Fig-3 shows the

variation of absorbed gamma dose rate (DR)with different locations.

Fig- 3. Absorbed Gamma Dose Rate (DR) with Different Locations

4.2. Annual effective dose rate (AEDE)

The annual effective dose rate (AEDE) in mSv y−1resulting from the absorbed

dose values (DR) was calculated using the following formula (UNSCEAR, 2000;

Ravisankar et al., 2012):

142

Ann. Eff. dose rate(mSvy−1) = DR(nGyh−1) ×8760h × 0.7 SvGy-1 × 0.2 × 10-6

AEDE = DR × × 0. 00123------------------- (2)

The annual effective dose (Table-2) ranged between 0.022 mSv y−1to 0.102

mSv y−1with a mean value of 0.044 mSv y−1.In normal background areas, the

average annualindoor effective dose from terrestrial radionuclides is0.46 mSv y−1

(UNSCEAR, 1993). Therefore, the obtained mean value from this study

(0.044 mSv y−1) is lower than the world average value. This indicates that the

sediment samples satisfy the criteria for a radiation safety point of view. Fig- 4

shows the variation of annual effective dose equivalent (AEDE) in different

locations

Fig- 4. Annual Effective Dose equivalent (AEDE) with Different Locations

4.3. External hazard index (Hex)

According to Beretka and Mathew, (1985) the external hazard index due to

gamma radiation was calculated using below formula which is given in Eq. (3)

----------------- (3)

Where AU, ATh and AK are the activity concentrations of 238U, 232Th and 40K

in Bq kg-1 respectively. The results of Hex are reported in Table-2. The Hex value of

the present work ranged between 0.095 and 0.512 with an average value 0.209. The

average Hex value (0.209) is very much lower when compared to the acceptable limit

of unity (Hex<1). It indicates that radiation hazards may not cause any harmful to

143

people living in the study area. Fig-5 shows the variation of external hazard index in

different locations.

Fig- 5. External Hazard Index (Hex) with Different Locations

5.0. Conclusion

(i) The activity concentrations of238U, 232Th and40K in sediments collected from

Thazhankuda to Rasappetai, Cuddalore, East coast of Tamilnadu had been

determined.

(ii) Using the activity concentrations of these radionuclides, radiological

hazard indices were evaluated in order to determine the effects ofthe natural

radionuclides in sediments.

(iv) The result indicates that average value of the each radiological hazard

parameter is well below the approved and recommended safety limits.

(v) From the analysis, there is no potential radiological health hazard may

directly be associated with the sediments from Thazhankuda to Rasappetai, East

coast of Tamilnadu.

(v) The results may be used as a reference data for monitoring possible

radioactivity pollutions in future.

Acknowledgement

Authors are highly indebted to Dr. B. Venkatraman, AD, RSEG, Indira

Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu for

permitting to do radioactivity analysis in his Division.

144

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Abdi, M.R., Hassanzadeh, S., Kamali, M., Raji, H.R., 2009. 238U, 232Th, 40K and 137Cs activityconcentrations along the southern coast of the Caspian Sea, Iran.

Marine PollutionBulletin. 58, 658-662.

Alam, M.N.,Chowdhury,M.I.,Kamal,M.,Ghose,S.,Islam,M.N.,Mustafa,M.N.,Miah,

M.M.H., Ansary,M.M., 1999.The 226Ra,232Th and 40K activatesinbeachsand

mineralsandbeachsoilsofCox’s bazaar,Bangladesh.J.Environ.Radioact.46,

243-250.

Al-Trabulsy,H.A.,Khater,A.E.M.,Habbani,F.I.,2011.Radioactivitylevelsand

radiological hazardindicesattheSaudicoastlineoftheGulfofAqaba.Radiat.

Phys.Chem.80,343–348.

Arogunjo, A.M., Farai, I.P., Fuwape, I.A., 2004. Dose rate assessment of terrestrial

gammaradiation in the delta region of Nigeria. Radiat. Prot. Dosim. 108, 73-

77.

Beretka, J., Mathew, P.J., 1985. Natural radioactivity of Australian building

materials.Industrial wastes and by products. Health Phys. 48, 87-95.

Chandramohan,J., Tholkappian, M., Harikrishnan, N., Ravisankar, R.,

2015.Assessment of Activity Concentrations of Radionuclides from

Pattipulam to Devanampattinam of East Coast of Tamilnadu, India using

Gamma Ray Spectrometry. International Journal of Frontiers in Science and

Technology. 3(3), 59-68.

El-Mamoney, M.H., Khater, A.E.M., 2004. Environmental characterization and

radioecological impacts of non nuclear industries on the Red Sea coast. J.

Environ. Radioact. 73,151–168.

Khatir, S.A., Ahamed, M.M.O., El-Khangi, F.A., Nigumi, Y.O., Holm, E., 1998.

Radioactivitylevels in the Red Sea coastal environment of Sudan. Marine

Pollution Bulletin 36,19-26.

Kurnaz, A., Ku cu ko merog lu, B., Keser, R., Okumusoglu, N.T., Korkmaz, F.,

Karahan, G.,Cevik, U., 2007. Determination of radioactivity levels and

hazards of soil and sedimentsamples in Firtina Valley (Rize, Turkey). Appl.

Radiat. Isot. 65, 1281–1289.

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Orgun, Y., Altinsoy, N., Sahin, S.Y., Gungor, Y., Gultekin, A.H., Karaham, G.,

Karaak, Z.,2007. Natural and anthropogenic radionuclides in rocks and beach

sands from Ezineregion (canakkale), Western Anatolia, Turkey. Appl. Radiat.

Isot. 65, 739-747.

Ravisankar, R., Chandrasekaran, A., Vijayagopal, P., Venkatraman, B.,

Senthilkumar, G.,Eswaran, P., Rajalakshmi, A., 2012. Natural radioactivity in

soil samples of YelagiriHills, Tamil Nadu, India and the associated radiation

hazards. Radiat. Phys. Chem. 81,1789-1795.

Ravisankar, R., Sivakumar, S., Chandrasekaran, A., PrincePrakashJebakumar, J.,

Vijayalakshmi, I., Vijayagopal, P., Venkatraman, B., 2014. Spatial

distribution of gamma radioactivity levels and radiological hazard indices in

the East Coastal sediments of Tamilnadu, India with statistical approach.

Radiation PhysicsandChemistry. 103, 89-98.

Saad, H.R., Al-Azmi, D., 2002. Radioactivity concentrations in sediments and their

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Radiation,2000.Sources, effects and risks of ionizing radiation. Report to the

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Uosif, M.A.M., El-Taher, A., Abbady, G.E., 2008. Radiological significance beach

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Umisedo, N.K., 2006.Measurements of natural radioactivity in Brazilian

beach sands. Radiat. Meas. 41, 189- 196.

146

SYNTHESIS AND CHARACTERIZATION OF NANO ALUMINA

BY TOP DOWN APPROACH

S. Vasudevan1 and P. Kavithamani2

1,2Dept. of Physics, Shanmuga Industries Arts and Science College, Tiruvannamalai

ABSTRACT

The alumina powder size reduced using planetary ball milling equipment

from micro to nano, this is confirmed by using scanning electrons microscope.

The hardness of the nano powder sintered samples offers the improved results

than micro particle sintered sample due to its reduced particle size without

damage. The density and porosity also offers the improved results in the nano

powder sintered samples due to the presents of less voids, close packed

arrangement of particles. The co-efficient of thermal expansion on the nano

alumina sintered samples shows improved results than micro alumina sintered

sample. The nano alumina sintered samples (pin or ball) will be suitable to

investigate the tribological property with or without temperature effect. Because

nowadays there is a new challenge to improve the tribological property by

synthesis the existing hard ceramics with respect to the temperature effects.

1. INTRODUCTION

Natural materials such as organic matter, mineral matter, and living

matter, along with artificial materials produced industrially, make up all of the

materials found on the Earth. They all have a chemical composition and

particular structure that give them specific properties or functions in relation to

their surroundings or their formation conditions.

Natural materials are formed in a particular environment, under the diverse

conditions seen in nature. These materials can be studied either in their original

state or after being modified. An artificial material is a compound manufactured

by synthesis under known conditions that are selected to give it specific

properties related to its field of application. Metal alloys, ceramics, and polymers

are some simple artificial materials. New materials are often made of complex

structures composed of mixed or composite materials [1-10].

147

When studying a material, the microscopist is confronted by the

relationships between its physical, chemical, thermal, and dynamic histories. The

conditions the material was subjected to will dictate its particular microstructure

formation at different scales, and thus its physical, chemical, and/or biological

properties. Regardless of the material type, three main parameters can be

presented such as (i) microstructure, (ii) growth related to its surroundings and

(iii) properties, which are interdependent [2]. If just one of these parameters

changes, then the other two are disrupted, sometimes irreversibly. The challenge

in developing new materials is to master all of the parameters of this system in

order to reproduce the properties or functions needed for a specific application.

Diverse materials result from the natural evolution of a rock, mineral, organic

material, or biological material or from the synthetic process for man-made

materials. In addition, the mechanisms of growth or formation are different

depending on whether materials are found in the solid state or liquid state or in

intermediary solid–liquid states [3]. Depending on the conditions of temperature,

pressure, chemical gradient, kinetics of diffusion (atomic, ionic, or molecular

diffusion), and thedynamics of the system, microstructures can be very diverse in

materials science.

2. MATERIALS AND METHODS :

2.1. MATERIALS:

Alumina is one of the most cost effective and widely used materials in the

family of engineering ceramics. The raw materials from which this high

performance technical grade ceramic is made are readily available and reasonably

priced, resulting in good value for the cost in fabricated alumina shapes. With an

excellent combination of properties and an attractive price, it is no surprise that

fine grain technical grade alumina has a very wide range of applications.

Aluminum oxide, commonly referred to as alumina, possesses strong ionic

interatomic bonding giving rise to its desirable material characteristics [11-12]. It

can exist in several crystalline phases which all revert to the most stable

hexagonal alpha phase at elevated temperatures. This is the phase of particular

interest for structural applications.

148

Alpha phase alumina is the strongest and stiffest of the oxide ceramics. Its

high hardness, excellent dielectric properties, refractoriness and good thermal

properties make it the material of choice for a wide range of applications [3].

High purity alumina is usable in both oxidizing and reducing atmospheres to

1925°C. Weight loss in vacuum ranges from 10–7 to 10–6 g/cm2.sec over a

temperature range of 1700° to 2000°C. It resists attack by all gases except wet

fluorine and is resistant to all common reagents except hydrofluoric acid and

phosphoric acid. Elevated temperature attack occurs in the presence of alkali

metal vapors particularly at lower purity levels.

The composition of the ceramic body can be changed to enhance particular

desirable material characteristics [8]. An example would be additions of chrome

oxide or manganese oxide to improve hardness and change color. Other additions

can be made to improve the ease and consistency of metal films fired to the

ceramic for subsequent brazed and soldered assembly.

Nanostructured materials are a broad class of materials, with microstructures

modulated in zero to three dimensions on length scales less than 100 nm.

These materials are atoms arranged in Nano sized clusters, which become the

constituent grains or building blocks of the material. Conventional materials

have grains sizes ranging from microns to several millimeters and contain several

billion atoms each. Nanometer sized grains contain only about 900 atoms each.

As the grain size decreases, there is a significant increase in the volume

fraction of grain boundaries or interfaces. This characteristic strongly

influences the chemical and physical properties of the material.

2.2. SYNTHESIS METHODS :

Synthesis is the act of combining elements to form something new. It is called

synthesis. Today synthesis of nanomaterial is a good challenge for achieving the

size controlled synthesis. Nanoscale materials are defined as a set of substances

where at least one dimension is less than approximately 100 nanometers. In

general there are two types of synthesis were followed in synthesizing nano-

materials.

Top-down approach

Bottom-up approach

149

Nanomaterials deal with very fine structures: a nanometer is a billionth of a

meter. This indeed allows us to think in either the ‘bottom up’ or the ‘top down’

approaches to synthesize nanomaterials, i.e. either to assemble atoms together or

to dis-assemble (break, or dissociate) bulk solids into finer pieces until they are

constituted of only a few atoms [13]. This domain is a pure example of

interdisciplinary work encompassing physics, chemistry, and engineering up to

medicine.

2.2.1. DENSITY AND POROSITY :

If an object is immersed in a fluid (a liquid or a gas), its apparent weight

will be less than its real weight by an amount equal to the weight of the fluid it

displaces. This is commonly referred to as Archimedes’ principleand is the

principle of buoyancy [1-7].

Wc = Wa - Ww

Where,Wc is the apparent weight of the object in the fluid (water),

Wais the real weight of the object in air, and

Ww is the weight of the displaced fluid (water).

The balances used in the lab are calibrated in mass units. However, they actually

respond to weight, the force of gravity acting downward on the object which is

placed on the balance. Since mass is linearly related to weight by w = mg, a

balance can be calibrated in grams.

2.2.2. DILATOMETER

A dilatometer is a scientific instrument that measures the length change of

a material as a function of change in temperature. Dilatometers are valuable tools

in the investigation of ceramics, particularly when measuring the dimensional

changes that occur upon sintering.

2.2.3. SCANNING ELECTRON MICROSCOPE (SEM)

Scanning electron microscopy (SEM) is a method for high-resolution

imaging of surfaces. The SEM uses electrons for imaging, much as a light

microscope uses visible light. The advantages of SEM over light microscopy

include much higher magnification (>100,000X) and greater depth of field up to

100 times that of light microscopy. Qualitative and quantitative chemical analysis

150

information is also obtained using an energy dispersive x-ray spectrometer (EDS)

with the SEM [4].

3. RESULTS AND DISCUSSION

The milled powders were characterized by scanning electrons microscope

at 30kev in the zooming range of 60,000X. But even though the particle was not

clearly reveal the edges, when the scanning electron microscope image was taken

in back scattered electron mode. This is due to the particle collision and high

charges applied on the surfaces, shows the white color presents more. When the

energy charges applied similar to the commercial un-milled powder (15Kev),

even though the particles not reveals clearly. In range to increasing the energy the

particle reveals clearly in the same place at the same zooming range. The shape

of the particle is evenly broken, this is due to the addition of process control

agent as a stearic acid.

Figure 3.1. (1) Alumina powder before milling, (2) Alumina powder after

milling, (3, 4) Alumina powder morphology of after milling at different energy

level

The tungsten carbide tools having more hardness when compared with

alumina, results improved size reduction rate. The mechanical milling parameters

like ball to powder ratio, milling speed are the reason for improved size

reduction. Because ball to powder ratio 10:1is offers the improved particle

151

breakage. Where the ratio between ball to powder increases the tool damage

occurs, decreases the size reduction rate gets reduced, also the milling speed of

250rpm is influenced on particle size reduction rate [14]. Because the speed

increases the balls are rotate in the top of the jar, when speed reduced the

breakage rate also gets reduce. Influence of process control agent on ball milling

of nano particle for even fracture achieved.

The sintering temperature is influenced on the nano particle joining to form a solid, also the holding time of 2hrs offers improved strength. Where the atmosphere cooling causes the formation of surface layer to reduce the properties [15]. Density of the sintered samples shows the nano particulates samples offers improved density then micro particulate samples, also the porosity level is high in the micro particulate samples. It is due to the particle size, presents of more voids between the particle arrangements [16]. The nano particulates offers the improved results of density and porosity, where compared to fully dense one.

Table: 1 Physical property of micro and nano sintered alumina

The hardness value of the nano particulate sample shows higher than micro samples. It is due to the reduced voids, porosity and closed arrangement of particulates, where compared with micro particulate samples. The Dilatometer results also offered the improved results on nana particulate samples. It is due to the particle size, when the particle size reduces the co-efficient of thermal expansion also gets reduce [17-19].

Table: 2 Thermal property of micro nano sintered alumina

S.no Temperature

(k)

Micro alumina

thermal expansion

(%)

Nano alumina

thermal expansion

(%)

1 423 6.73 6.68

2 473 6.78 6.71

3 523 6.86 6.75

4 573 6.95 6.8

S.no Sample

name

Density

(g/cm3)

Porosity

(%)

Vickers hardness

(Hv)

1 Micro

sample 3.82 0.04 1597

2 Nano

sample 3.91 0.01 1612

152

4. CONCLUSION

The planetary ball milling equipment was used to reduce the alumina

powder size from micro to nano, this is confirmed by using scanning electrons

microscope. While mechanical milling the milling parameters were influenced

the size reduction without particle damage from its initial condition. The stearic

acid is influenced on the cold welding on the particle breakage, also avoids the

agglomeration of the particles. The milling speed (250rpm) and balls to powder

(10:1) ratio contributes the particle fracture rate. The hardness of the nano

powder sintered samples offers the improved results than micro particle sintered

sample due to its reduced particle size without damage. The density and porosity

also offers the improved results in the nano powder sintered samples due to the

presents of less voids, close packed arrangement of particles. The co-efficient of

thermal expansion on the nano alumina sintered samples shows improved results

than micro alumina sintered sample.

From the above obtained conclusions, this nano alumina sintered samples

(pin or ball) will be suitable to investigate the tribological property with or

without temperature effect. Because nowadays there is a new challenge to

improve the tribological property by synthesis the existing hard ceramics with

respect to the temperature effects. So, I will take this investigation to improve the

tribological property of the bearing application in the future. Because the nuclear

industries are currently using the alumina ball bearings in the nuclear power plant

feed pumps.

So in this future I will planned to continue the same work to investigate

the tribological property of the nano alumina pin or ball against with SAE52100

bearing steel. Also trying to investigate the tribological property of the same

material sintered by Spark Plasma Sintering (SPS) technique. Because, this is a

conventional sintering technique to improve the physical, mechanical and

tribological property.

REFERENCES

1. Ashby, M. F., and D. R. H. Jones, “Engineering Materials 1, An Introduction to

Their Properties and Applications”, 3rd edition, Butterworth-

Heinemann,Woburn, UK, 2005.

153

2. Ashby, M. F., and D. R. H. Jones, “Engineering Materials 2, An Introduction to Microstructures”, Processing and Design, 3rd edition, Butterworth-Heinemann,Woburn, UK, 2005.

3. William D. Callister, Jr., “Fundamentals of Materials Science and Engineering”, fifth edition, John Wiley & Sons, Inc.

4. William d. Callister, jr., david g. Rethwisch, “Materials Science and Engineering an Introduction”, eighth edition, John Wiley & Sons, Inc.

5. Cowie, J. M.G., and V. Arrighi, “Polymers: Chemistry and Physics of Modern Materials”, 3rd edition, CRC Press, Boca Raton, FL, 2007.

6. Shackelford, J. F., “Introduction to Materials Science for Engineers”, 7th edition, Prentice Hall PTR,Paramus, NJ, 2009.

7. White, M. A., “Properties of Materials”, OxfordUniversity Press, New York, 1999.

8. Kingery, W. D., Bowen, H. K., and Ulhmann, D. R., "Introduction to Ceramics," 2nd ed. Wiley (Interscience), New York, 1976.

9. Levenspiel, O., "Chemical Reaction Engineering," pp. 270-300. Wiley, New York, 1972.

10. Terry A. Ring, “Fundamentals of Ceramic Powder Processing and Synthesis”, Academic Press, 1996.

11. Perttiauerkari, “Mechanical and physical properties of engineering alumina ceramics”, VTT manufacturing technology, technical research center of Finland, Espoo 1996.

12. Shinji FUJIWARA, Yasuaki TAMURA, Hajime MAKI, Norifumi AZUMA, Yoshiaki TAKEUCHI, “Development of New High-Purity Alumina”, SUMITOMO KAGAKU”, vol. 2007-I.

13. MałgorzataSopicka-Lizer, “High-energy ball milling Mechanochemical processing of nanopowders”, Woodhead Publishing Limited, 2010.

14. A. Eskandari, M. Aminzare, Z. Razavihesabi, S.H. Aboutalebi, S.K. Sadrnezhaad, “Effect of high energy ball milling on compressibility and sintering behavior of alumina nanoparticles”, Ceramics International 38 (2012) 2627–2632.

15. H. Ferkel, R.J. Hellmig, “Effect of nanopowderdeaglomeration on the densities of nanocrystalline ceramic green bodies and their sintering behavior”, Nanostruct. Mater. 11 (1999) 617–622.

16. M.A. Meyers, A. Mishra, D.J. Benson, “Mechanical properties of nanocrystalline materials”, Prog. Mater. Sci. 51 (2006) 427–556.

17. ASM Ready Reference: Thermal Properties of Metals, 2002 ASM International 18. R.E. Taylor, “CINDAS Data Series on Materials Properties, Thermal Expansion

of Solids”, Vol 1–4, ASM International, 1998. 19. “Standard Test Method for Linear Thermal Expansion of Solid Materials by

Thermomechanical Analysis,” E 831, Annual Book of ASTM Standards, ASTM, 2000.

154

ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL

ON THE MICELLATION OF SURFACTANT IN

AQUEOUS SOLUTION AT FIXED FREQUENCY 2 MHZ

AND FIXED TEMPERATURE OF 303.15K.

G. Lakshiminarayanan1 and D. Arun kumar2

1,2 Department of Physics, Shanmuga Industries Arts and Science College,

Thiruvannamalai.

ABSTRACT

Ultrasonic velocity, density and viscosity studies have been carried out in

aqueous solutions of sodium oleate and in aqueous solutions of sodium oleate

containing 5-20% V/V of methanol (ME). These studies are carried out in sodium

oleate concentration of 3mM to 12mM at a fixed frequency of 2MHz and at a fixed

temperature of 303.15K. The variation of ultrasonic velocity in aqueous solutions of

sodium oleate containing 5-20% V/V of ME sodium oleate concentration exhibiting

a break at critical micelle concentration (CMC). The ultrasonic velocity, adiabatic

compressibility, free length, free volume and internal pressure also exhibiting a

break at CMC similar to velocity curve. The results are discussed in terms of

formation of sodium oleate micelles through hydrophobic interaction and hydrogen

bonding.

INTRODUCTION

Molecular interaction in liquid mixtures has been the subject of numerous

investigation in recent past years [1-3]. The system shows a wide verity of physical

properties. Recent researchers have studied the interaction of sodium oleate (SO)

with various additive through ultrasonic techniques. But the effect of methanol on

SO is scandy. The aim our present investigation is to determine ultrasonic studies

on the effect of methanol on the micellization of sodium oleate in aqueous

solutions at fixed frequency of 2 MHz and fixed temperature of 303.15 k. The

results are interpreted in terms of formation of SO micelles in the solutions.

155

MATERIALS AND METHODS

The sodium oleate (SO) used in the present study are of AR/BDH grade

purchased from SD-fine chemicals Ltd., India and they are used as such without

further purification. The solvents used namely methanol are of spectroscopic grade.

Triply distilled deionised water is used for preparing the solutions of methanol.

Ultrasonic velocity studies are carried out at a fixed frequency of 2 MHz in the

sodium oleate concentration range of 3mM to 12mM. Ultrasonic velocity is

measured using a Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-

Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at 303.15K by

circulating water from a thermostatically controlled water bath and the temperature

being maintained to an accuracy of ±0.1oC. The accuracy in measurement of

velocity and absorption is ±2 parts in 105 and 3% respectively. Shear viscosity and

density of aqueous solutions of SO containing 5-20% V/V of ME are determined

using an Oswald’s viscometer and a graduated dilatometer respectively. The

accuracy in measurement of density and viscosity is ±2 parts in 104 and ± 0.1%

respectively. From the measured values of ultrasonic velocity, density and viscosity,

the various other parameters such as adiabatic compressibility (βs), intermolecular

free length (Lf), free volume (Vf ) and internal pressure (Пi) are calculated using

standard formulae.

COMPUTATIONS OF PARAMETERS

Adiabatic compressibility (βs), intermolecular free length (Lf), free volume

(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),

respectively.

βs = 1/C2ρ (1)

Lf = KT βs 1/2 (2)

Vf = (M C / K η)3/2 (3)

πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)

where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M

is effective molecular weight, K is constant for liquids, b is constant, T is

temperature.

156

RESULT AND DISCUSSIONS

From the measured values of ultrasonic velocity and viscosity, the other

parameters such as adiabatic compressibility, free length, free volume and internal

pressure were computed and shown in graphically in figures (1-6).The variations of

ultrasonic velocity against concentration of sodium oleate in aqueous solution are

given in Fig 1. The measured ultrasonic velocity increases with increasing

concentration of sodium oleate in aqueous solutions and exhibits sharp break at a

particular concentration is known as Critical Micellar Concentration (CMC), which

is confirmed by G.Ravichandran et al [4]. The increase in ultrasonic velocity before

CMC is due to the oleate ions making hydrogen bond with water molecules. The

micelle formation in aqueous solution of sodium oleate and higher aggregation leads

to increase in velocity beyond CMC.

The measured ultrasonic velocity increases with increasing concentration of

sodium oleate in aqueous – alcoholic solvent (5-20%V/V of methanol) mixtures of

solution and exhibits sharp break at a particular concentration of sodium oleate

(i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity is due to the

alcoholic solvents act as a structure breaker in aqueous sodium oleate. Sodium ions

are restricting the mobility of the water molecules. This leads to increase in

ultrasonic velocity in pre-micellar solution. The micelle formation in aqueous-

alcoholic solution of sodium oleate and higher aggregation leads to increase in

velocity for post micellar solution. In addition to average dipole moment of sodium

oleate in the solution also contributes increase in ultrasonic velocity. The velocity

observed in aqueous-alcoholic solvent at particular compositions (volume by

volume) in the order:

Velocity of 5% ME mixture < Velocity of 10 % ME mixture < Velocity of 15 % ME

mixture <Velocity of 20 % ME mixture

From the figure 1, it is observed that when the 5% V/V of methanol is added

to the aqueous solution of sodium oleate, the CMC of aqueous solution of sodium

oleate shifted towards the higher concentration side (6.5 mM). This is due to the

lowering of the average dielectric constant of the medium because of the dielectric

constant of water is greater than methanol.

157

Similarly, when the 10-20% V/V of methanol is added to the aqueous solution

of sodium oleate the CMC of aqueous solution of sodium oleate shifted towards the

higher concentration side in the order of (7.0 mM), (8.0 mM), (8.5 mM),

respectively.

Adiabatic compressibility, free length and free volume, internal pressure

studies supports the ultrasonic velocity studies in aqueous and aqueous alcoholic

solvents mixtures.

CONCLUSION

In the present study, the ultrasonic velocity, density, viscosity and internal

pressure increases whereas adiabatic compressibility, free length and free volume

decreases with increasing concentration of sodium oleate in aqueous and aqueous –

alcoholic mixture (Methanol).

The CMC value obtained in with aqueous with 20 % V/V alcoholic solvent

(Methanol) mixture is greater than all other compositions of alcohols concentrations

of sodium oleate solutions. This is due to the higher breaking nature of alcohol in

higher compositions.

0.002 0.004 0.006 0.008 0.010 0.012

1565

1570

1575

1580

1585

1590

1595

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

Ultr

ason

ic V

eloc

ity (m

s-1)

Molar Concentration of Sodium Oleate

0.002 0.004 0.006 0.008 0.010 0.012

8.0

8.5

9.0

9.5

10.0

10.5

11.0

Visc

osity

10-4

NSm

-2

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

Figure-1 Figure-2

158

0.002 0.004 0.006 0.008 0.010 0.0124.17

4.18

4.19

4.20

4.21

4.22

4.23

Free

Len

gth

L f x 1

0-10 m

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

0.002 0.004 0.006 0.008 0.010 0.0124.04

4.06

4.08

4.10

4.12

4.14

4.16

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

Adi

abat

ic C

ompr

essi

bilit

y( b

s )X10

-10 N

-1m

2

Molar concentration of Sodium Oleate

0.002 0.004 0.006 0.008 0.010 0.0123.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

5.0

5.2

5.4

Free

vol

ume

(Vf) m

3

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

0.002 0.004 0.006 0.008 0.010 0.0122.90

2.95

3.00

3.05

3.10

3.15

3.20

3.25

3.30

3.35

3.40

Water + SO Water + 5 % ME + SO Water + 10 % ME + SO Water + 15 % ME + SO Water + 20 % ME + SO

Inte

rnal

Pre

ssur

e (p

i) pa

scal

Molar Concentration of Sodium Oleate

Figure-3 Figure-4

Figure-5 Figure-6

References

1. Bhattarai A, Chatterjee SK, Deo TK, Niraula TP (2011) Effects of concentration, temperature, and solvent composition on the partial molar volumes of sodium lauryl sulfate in methanol (1) + water (2) mixed solvent media. J Chem Eng Data 56:3400–3405

2. Nain AK, et al. Molecular interactions in binary mixtures of formamide with 1 butanol, 2 butanol, 1,3butaneol at different temperatures. Journal of Fluid Phase Equilibria, 2008; 265(1-2):46-56.

3. Bhoj Bhadur Gurung, Mahendra Nath Roy, Study of densities, viscosities and ultrasonic speeds of binary mixtures containing 1, 2 diethoxy ethane with alkane 1-ol at 298.15 K. Journal of Solution Chemistry. 2006; 35:1587-1606.

4. G.Ravichandran, G.rajarajan, T.K. Nambinarayanan, Journal of Molecular Liquids 267-276, 102 (2003).

159

NMR , NBO, AND VIBRATIONAL SPECTROSCOPIC ANALYSIS OF

O-NITROBENZAMIDE

D.Nandha kumara, P.Manib

aDepartment of Chemistry, Sanghamam college of arts and science,

Annamangalam,Gingee – 604210. bDepartment of physics, Shanmuga industries Atrs and science

College,Thiruvannamalai – 606603.

ABSTRACT

In the present methodical study, FT-IR, FT-Raman and NMR spectra of

o-nitrobenzamide are recorded and fundamental vibrational frequencies are tabulated

assigned. The vibrational wavenumbers were computed using HF and DFT methods.

The assigned with potential energy distribution method. Gaussian hybrid

computational calculations are carried out using HF and DFT (B3LYP and B3PW91)

methods with 6-31+G (d,p), cc-pVDZ and aug-cc-pVDZ basis sets. Moreover, 1H

and 13C NMR spectra have been analysed 1H and 13C nuclear magnetic resonance

chemical shifts are calculated using the gauge independent atomic orbital (GIAO)

method. A study on the electronic and optical properties (absorption wavelengths,

excitation energy, and dipole moment frontier molecular orbital energies) is

performed using HF and DFT methods. Stability of the molecule arising from hyper

conjugative interactions, charge delocalization has been analysed using natural bond

orbital (NBO) analysis.

Keywords: o-nitrobenzamide; gauge-independent atomic orbital; chemical shifts;

Introduction

O-nitrobenzamide is an organic compound, which consists of nitro; carbonyl

and amide groups are attached to the phenyl ring. It reacts with azo and diazo

compounds to generate toxic gases. Flammable gases are formed by the reaction of

O-nitrobenzamide with strong reducing agents. O-nitrobenzamide is very weak

bases.It is a stable compound and does not undergo polymerization. O-

nitrobenzamide is easily oxidized by using Strong oxidizing agents. Exposure to air

or moisture over prolonged periods destroys the nature of the amide.

160

The IUPAC namLe of O-nitrobenzamide is 2-Nitrobenzamide. The molecular

formula of O-nitrobenzamide is C7H6N2O3 and the molecular weight is 166.13. It is a

kind of beige crystalline powder and belongs to the classes of Aromatic Carboxylic

Acids, Amides, Anilides and Carbonyl Compounds; Organic Building Blocks. Other

synonyms of o-nitrobenzamide: 2-Nitrophenylformamide;benzamide, o-

nitro-;2-Carbamoylnitrobenzene.

2. Computational methods

In the present work, HF and some of the hybrid methods, B3LYP and B3PW91,

are carried out using the basis sets 6-31+G (d,p) and cc-pVDZ & aug-cc-pVDZ. All

these calculations are performed using the GAUSSIAN 09W [3] program package on

an i7 processor in a personal computer. In DFT methods, B3LYP is the combination

of Becke’s three-parameter hybrid function, and the Lee–Yang–Parr correlation

function [4, 5]. B3PW91 is the combination of Becke’s three parameter exact

exchange-function (B3) [6] and Perdew-Wang (PW91) correlation function [7, 8]. The

optimized molecular structure of the molecule is obtained using the Gaussian 09 and

Gaussview program and is shown in Fig. 1. The comparative optimized structural

parameters such as bond length, bond angle and dihedral angle are presented in

Table 1. The observed (FT-IR and FT-Raman) and calculated vibrational frequencies

and vibrational assignments are presented in Table 3. Experimental and simulated

spectra of IR and Raman are presented in Fig. 2 and 3, respectively.

The 1H and 13C NMR isotropic shielding are calculated using the GIAO method

[9] and the optimized parameters obtained from the B3LYP/cc-pVDZ method. 13C

isotropic magnetic shielding (IMS) of any X carbon atoms is made according to the 13C IMS value of TMS, CSX = IMSTMS-IMSx. The 1H and 13C isotropic chemical

shifts of TMS (Tetramethylsilane) in gas, DMSO, methanol and ethanol are

calculated using IEFPCM method with the B3LYP functional at the cc-pVDZ level.

The absolute chemical shift is found between the isotropic peaks and the peaks of

TMS [10]. Stability of the molecule arising from hyper conjugative interactions,

charge delocalization is analyzed using natural bond orbital (NBO) analysis.

161

4. Results and discussion

4.1. Molecular geometry

FroUm the optimized output file of Gaussian it is observed that the molecular

structure of o-nitrobenzamide belongs to C1 point group symmetry. The optimized

structure of the molecule is obtained from the Gaussian 09 and Gauss view program

[13] and is shown in Fig. 1. The present molecule contains one nitro group and one

amide group, which are loaded in the left moiety. The hexagonal structure of the

benzene is deformed at the point of substitution due to the addition of the heavy

mass. It is also evident that the bond length (C1-C2 & C2-C3) at the point of

substitution is 0.0054 Å, which is longer than the rest in the ring. Consequently, the

property of the same also changed with respect to the ligand (nitro and amide

groups). The bond angle of C1–C2–C3 is 2.0151º elevated than C4–C5–C6 in the

ring, which also confirms the deformation of the hexagonal shield. Although both

C=O and NH2 groups, the bond length values between C2–C3 and C3–C11 differed

by 0.121 Å. The entire C–H bonds in the chain and the amide groups have almost

equal inter-nuclear distance.

Figure 1: Molecular structure of O-Nitrobenzamide

4.2. Vibrational assignments

In order to obtain the spectroscopic significance of o-nitrobenzamide, the

computational calculations are performed using frequency analysis. The molecule

has C1 point group symmetry, consists of 18 atoms, so it has 48 normal vibrational

modes. On the basis of C1 symmetry, the 48 fundamental vibrations of the molecule

can be distributed as 36 in-plane vibrations of A species and 12 out-of-plane

162

vibrations of A species, i.e., vib = 36 A + 12 A. In the C1 group, the symmetry of

the molecule is a non-planar structure and has 48 vibrational modes that span in the

irreducible representations.

The vibrational frequencies (unscaled and scaled) calculated at HF, B3LYP and

B3PW91methods with 6-311+G(d,p), cc-pVDZ and aug cc-pVDZ basic sets and

observed FT-IR and FT-Raman frequencies for various modes of vibrations have

been presented in Tables 2 and 3. The Frequencies calculated at the HF and

B3LYP/B3PW91 methods are found to be high compared to experimental vibrations.

The Inclusion of electron correlation in the density functional theory to a certain

extent makes the frequency values smaller in comparjison with the HF frequency

data.

The calculated frequencies are scaled down to give up the rational with the

observed frequencies. The scaling factors are 0.8889, 0.9390, 0.9999 and 0.9909 for

HF/6-31+G (d, p). For the B3LYP/cc-pVDZ/aug-cc-pVDZ basis set, the scaling

factors are 0.9544, 1.0174, 1.0919 and 1.0881/0.9578, 1.0207, 1.0976 and 1.0929.

For the B3PW91/ cc-pVDZ/aug-cc-pVDZ basis set, the scaling factors are 0.9466,

1.0105, 1.0939 and 1.0871/0.9511, 1.0125, 1.0968 and 1.0921.

4.2.1. N H, N=O vibrations

In heterocyclic molecules, the N H stretching vibrations have been measured

in region 3500–3000 cm–1 [14]. As seen in Table 2, the two N H stretching modes are

calculated at 3494 and 3372 cm–1 in B3LYP. A very strong FT-IR N H stretching

vibration is observed at 3390 cm–1 in the experimental spectrum. Ten et al. [15] have

observed these modes at 3479 and 3432 cm–1, respectively, for isolated thymine. In

2-amino-4-methylbenzothiazole, V. Arjunan et al [16]. have observed the vibrational

frequencies at 3417 and 3287 cm−1. Cirak and Koc [17] have calculated the N–H

stretching modes at 3189 and 3155 cm−1 for dimeric trifluorothymine. However, no

Raman band is observed for the N H stretching modes in the experimental spectra.

For primary amino group the in-plane –NH2 deformation vibration occur in the short

163

range 1650–1580 cm−1 region of the spectrum. Therefore the very weak band

observed in IR at 1570 cm−1 is assigned to the deformation mode of the amino group.

The most characteristic bands in the spectra of nitro compounds are due to

NO2 stretching vibrations, which are the most useful group wavenumbers, not only

because of their spectral position but also for their strong intensity [18]. The N=O

stretching vibrations have been measured in region 1515-1560 cm–1. A weak IR

N O stretching vibration is observed at 1430 cm–1. However, no Raman band is

observed for the N=O stretching modes. Hence these vibrations show good

agreement with the literature values.

4.2.2. C–H Vibrations

The C–H stretching vibrations are normally observed in the region 3100-3000

cm−1 for the aromatic benzene structure, [19–20] which shows their uniqueness of the

skeletal vibrations. The bands appeared at 3100, 3090, 3080, and 3050 cm−1 in o-

nitrobenzamide are assigned to C–H ring stretching vibrations. The FT-IR bands at

1520 and 1470 cm−1 are assigned to C–H in-plane bending vibrations and FT-IR

bands at 860 cm−1 are assigned to C–H out-of-plane bending vibration. V.

Karunakaran et al. [21] in the molecule 4-chloro-3-nitrobenzaldehyde (CNB) have

observed the bands at 3053, 3034 cm−1 in FT-IR and at 3079, 3052 cm−1 in FT-

Raman spectra. The FT-IR bands at 1467, 1422 cm−1 and the FT-Raman bands at

1423 and 1218 cm−1 were assigned to C–H in-plane bending vibration of CNB. The

C–H out-of-plane bending vibrations of the CNB were well identified at 989, 822

and 722 cm−1 in the FT-IR and 828 cm−1 in the FT-Raman spectra V. Arjunan et al.

[22] in 4-acetyl benzonitrile, have been observed the C–H stretching peaks in IR at

3075 and 3030 cm−1 and in Raman spectrum at 3090, 3074 and 3025 cm−1. The

frequencies calculated for the present compound using B3LYP/cc-pVDZ and

B3LYP/aug cc-pVDZ methods for C–H in-plane bending vibrations showed

excellent agreement with the recorded spectrum as well as literature data.

4.2.3. C–C vibrations

V. Arjunan et al [23] in 4-acetyl benzonitrile, have observed the C–C

stretching vibrations at 1593, 1556, 1485, 1415, and 1259 cm−1 in IR spectrum and

1603, 1482, 1430, 1408 and 1270 cm−1 in Raman spectrum. The IR bands observed

164

at 1593 and 1285 cm−1 were strong while the Raman band 1603 cm−1 was very

strong. In addition, C–C–C in–plane bending vibrations have been attributed to 1002

and 844 cm−1 in IR spectrum and 794 cm−1 in Raman spectrum. The C–C–C out of

plane vibrations have observed at 337, 227 and 108 cm−1 in Raman spectrum. V.

Karunakaran et al.[24] in the molecule 4-chloro-3-nitrobenzaldehyde have observed

the C–C stretching vibrations at 1589, 1356, 1200 and 1056 cm−1 in FT-IR spectrum

and at 1626, 1372, 1160 and 1058 cm−1 in Raman spectrum.

The bands due to the C–C stretching vibrations are called skeletal vibrations

normally observed in the region 1430–1650 cm1 for the aromatic ring

compounds.[25, 26] Socrates [27] mentioned that the presence of a conjugate substituent

such as C=C causes stretching of peaks around the region of 1625–1575 cm1. As

predicted in the earlier references, in this title compound, the prominent peaks are

found with strong and medium intensity at 1600 and 1590 cm1 due to C=C

stretching vibrations. The C–C stretching vibrations are appeared at 1580, 1520,

1470 and 1400 cm1. The C-C out-of-plane bending vibrations are appeared at 1130,

1090, 1000 and 970 cm1.

4.2.4. C N vibrations

The C N vibration of the compound identification is a very difficult task,

since the mixing of several bands is possible in the region. Silverstein et al. [28]

assigned C N stretching absorption in the region 1382–1266 cm–1 for aromatic

amines. In benzamide the band observed at 1368 cm–1 is assigned due to C N

stretching [29]. However with the help of force field calculations, the C N vibrations

are identified and assigned in this study. A. Prabakaran et al.[30] in 7-(1,3-

dioxolan-2-ylmethyl)-1,3-dimethylpurine-2,6-dione (7DDMP26D) have observed C–

N, C=N stretching vibrations at 1478.19 and 1280.19 cm–1 in FT-IR spectrum and at

1480.00 and 1280.53 cm–1 in FT-Raman spectrum respectively. In our present work,

C N stretching vibrations are observed at 1400 and 1180 cm–1 in FT-IR spectrum.

This band has been calculated at 1403 cm–1 by DFT method and at 1180 cm–1 by HF

method are very good agreement with experimental values.

165

4.2.5. C=O vibrations

The C=O stretching frequency appears strongly in the IR spectrum in the

range 1600–1850 cm–1 because of its large change in dipole moment. The carbonyl

group vibrations give rise to characteristics bands in vibration spectra and its

characteristic frequency used to study a wide range of compounds. The intensity of

these bands can increase owing to conjugation or formation of hydrogen bonds [31].

Carthigayan et al. [32] have observed the bands at 1822 and 1842 cm–1 in the infrared

spectrum corresponds to C=O stretching in 4,5-Bis(bromomethyl)-

1,3-dioxol-2-one (45BMDO). The corresponding frequency of 4-Bromomethyl-5-

methyl-1, 3-dioxol-2-one (4BMDO) was observed at 1820 cm–1. A very strong IR

absorption band at 1680 cm–1 is readily assigned to the carbonyl vibration in the o-

nitrobenzamide; the corresponding DFT computed mode at 1720 cm–1 at B3LYP/cc-

pVDZ, level is good agreement with the observed one.

4.3. NBO analysis

The second order perturbation NBO Fock matrix was carried out to evaluate

the donor–acceptor interactions in the NBO analysis. The interaction result is a loss

of occupancy from the localized NBO of the idealized Lewis structure into an empty

non-Lewis orbital. For each donor (i), and acceptor (j), the stabilization energy E(2)

associated with the delocalization i j is estimated as

Natural bond orbital analysis provides an efficient method for studying intra

and intermolecular bonding and interaction among bonds, and also provides a

convenient basis for investigating charge transfer or conjugative interaction in

molecular systems [33].The intra molecular hyper conjugative interactions of π (C1–

C2) to π* (N16–O17) leads to highest stabilization of 24.54 kcal mol-1. In case of π

(C1–C2) orbital the π*(C3–C4) shows the stabilization energy of 21.84 and 17.61

kcal mol-1. Similarly in the case of π (C3–C4) to π* (C1–C2) and π* (C5–C6) anti-

bonding orbital leads to stabilization energy of 20.80 and 21.38 kcal mol-1 and from

π (C5–C6) to π* (C1–C2), π*(C3–C4) has stabilization energies of 23.46 and 19.18

166

kcal mol-1, respectively are listed in Table 4. The π – π* transition and corresponding

perturbation energy are shown in figure 4.

4.4. NMR assessment

NMR spectroscopy is currently used for the structural elucidation of complex

molecules. The combined use of experimental and computational tools offers a

powerful gadget to interpret and predict the structure of bulky molecules. The

optimized structure of o-nitrobenzamide is used to obtain the NMR spectra

supported by the GIAO method with B3LYP functional at the cc-pVDZ basic set,

and the chemical shifts of the compound are reported in ppm relative to TMS for 1H

and 13C NMR spectra, which are presented in Table 5. The corresponding spectrum

is shown in Fig. 5 & 6. 13C NMR chemical shifts for similar organic molecules usually are >100 ppm .

The accuracy ensures reliable interpretation of spectroscopic parameters. In the case

of o-nitrobenzamide, the chemical shifts of C1, C2, C3, C4, C5, C6, and C11 are

132.429, 144.929, 122.479, 120.791, 118.984, 122.882 and 179.985 ppm

respectively. The shift is higher in C2 and C11 than the others.

All the carbon atoms in the molecule are found to have higher chemical shifts it

is because of presence of highly negative atoms attached to the carbons. Among this

C11 atom has higher chemical shift compared to all other atoms. It is due to

attachment of electrons withdrawal amide carbonyl functional group.

The calculated values are compared with the experimental values. It is found that

the calculated values are higher than the experimental values. And the lower peaks of

hydrogen in experimental spectrum is found missing.

5. Conclusion

In the geometrical study, it is observed by the calculation of the bond length

and bond angle, the hexagonal structure of the compound is deformed. In the

vibrational study though most of the vibrations are in line with the literature some

the mode carbonyl group is shifted to the end position of the range. The NMR

reveals that the C11 atom which is attached to the carbonyl and amine group has

167

more shift compared all other atoms in the compound; it means that atom is more

deshielded by its electrons.

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Effect of annealing process on structural, morphological, electrical and

optical properties of CeO2 nanoparticles synthesized by Chemical precipitation

method

K. Mohanraj1, D. Balasubramanian*1, N. Jhansi1, R. Suresh2, C. Sudhakar3 1Raman Research Laboratory, PG & Research Department of Physics, Government

Arts College, Tiruvannamalai-606603 2Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and

Science, Coimbatore- 20 3PG & Research department of Chemistry, Government Arts College,

Tiruvannamalai-606603

Corresponding author: mohan1991mpt@gmail.com Mobile: +91 9677971999

Abstract

Cerium oxide nanoparticles are successfully synthesized by Chemical

precipitation method. Effect of annealing process on the crystallite growth of cerium

oxide nanoparticles properties are investigated by various XRD, SEM, PL and I–V

studies. Crystallites are detected by X-ray diffraction pattern with preferred

orientation along (111) direction. Annealing temperature affects the crystallinity and

structural parameters like grain size, texture coefficient, and dislocation density. PL

spectra revealed that strong and broad emission band is observed at 425 nm due to

the presence of blue shift in the visible region. Large agglomerated spheroid

crystallites are obtained with the typical size in the range 4–12 nm.

Keywords: Cerium oxide nanoparticles, Structural, Morphological, Optical

properties.

1. Introduction

Nanomaterials contain particles with one dimension in the nanometer regime.

Now days, there is a growing interest from the scientific community in the

applications of these nanomaterials which is sometimes referred to as “the next

industrial revolution” [1]. Nanoparticles have received much attention in the field of

material science because of their fascinating mechanical and physic chemical

properties which are entirely different from their bulk counterparts. Semiconductor

170

nanoparticles are of great interest due to their electronic and optical properties [2].

Among these semiconductor nanoparticles, cerium oxide has been of great interest in

versatile applications due to its chemical stability and close lattice parameter with

silicon [3]. It is a noticeable functional material with an extraordinary capacity to

store and release oxygen with cubic fluorite structure [4]. Among oxides, the cubic

CeO2 phase (fluorite) has long been considered as one of the most promising

materials because of high refractive index, good transmission in visible and infrared

regions, strong adhesion, and high stability against mechanical abrasion, chemical

attack and high temperatures [5]. Several methods have been adopted for the

preparation of ultrafine ceria nanoparticles including Co-precipitation, hydrothermal,

pyrolysis, reverse micelles, sol–gel, sonochemical, solvothermal and simple

precipitation method. Among these methods, ammonia precipitation method is

widely adopted in laboratories because of its low preparation cost and simple

process.

It has fascinated substantial attention of researchers because of its wide band

gap and considered as a promising material for automobile exhaust, buffer layers,

catalyst, filters, gas sensors, solid oxide fuel cells (SOFC).

In the present work, the crystallographic structures, surface morphology,

optical properties and I–V characteristics as a function of annealing temperatures

prepared by chemical precipitation method using cerium nitrate as the source

material are investigated and presented.

2. Experimental details

Cerium oxide (CeO2) nanoparticles are prepared using cerium nitrate and

aqueous ammonia purchased from HIMEDIA, Mumbai. In the process of synthesis,

0.1 M of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) is dissolved in 50 ml of

deionized water and strongly stirred for 30 min, then 25 ml of aqueous ammonia

solution is added dropwise to the above solution for 20 min and stirred for 10 h at

room temperature. Interesting changes appeared in color of the solution when

precipitant was added to cerium nitrate solution.

Initially at low pH slurry is light brown, possibly due to Ce3+, which is turned

into light white–black in 2 h, then turned into brown after 3 h, then light or orange

for 5 h, finally light yellow due to the formation of Ce4+ in the presence of oxygen.

171

The obtained slurry is filtered and washed several times with deionized water and

ethanol. The washed precipitate is dried in oven at 60 C for 3 h. The dried powders

are well grinded for 15 min using mortar pestle and annealed to 450 and 900 C for 2

h to enhance the crystallinity of the samples. The synthesis mechanisms may be

described by the following reactions.

Ce(NO3)3 · 6H2O + 2NH4OH CeO2+ 2NH4(NO3) +NO2 +7H2O450-900 oC

A precipitate is obtained by adding solution to NH4OH. The formation of

cerium hydroxide after oxidation of Ce3+ to Ce4+ at high pH is obtained and then

cerium hydroxide is converted into cerium oxide with the removal of hydroxyl

group.

3. Results and discussion

3.1 X-ray diffraction analysis

172

Figure 3.1 XRD patterns of CeO2 nanoparticles

Table 1. Structural Properties of Cerium Oxide nanoparticles

Sample

name

2 Theta

(Degree)

FWHM

( Å) hkl

Crystallite

Size (nm)

Dislocation

Density Strain

Stacking

Fault

Texture

Coefficient

Lattice

Constant

(Å)

as-

prepared

28.3847

33.1036

47.4956

59.1285

69.2523

0.7144

0.6494

0.4546

0.7793

0.9504

1 1 1

2 0 0

2 2 0

2 2 2

4 0 0

11.9

13.3

19.9

12.2

10.6

7.24

5.06

1.60

3.47

4.00

3.15

2.43

1.15

1.53

1.53

0.3594

0.3013

0.1733

0.2617

0.2893

1.14306

1.10495

1.09601

0.67445

0.98159

5.446

5.412

5.412

5.412

5.422

Annealed

450oC

28.4372

33.2547

47.6549

0.2273

0.7144

0.7144

1 1 1

2 0 0

2 2 0

37.6

12.0

12.6

0.73

6.34

3.95

1.00

2.75

1.80

0.1142

0.3307

0.2719

1.16917

0.99964

1.06889

1.08844

5.436

5.389

5.384

173

Crystal structure and phase identification of the samples are analyzed from

the X-ray diffraction pattern. XRD pattern of Cerium oxide powders confirmed the

presence of cubic fluorite structure with preferred orientation along (111) direction

as shown in Fig. 4.1 a-c. All Bragg peaks with miller indices (111), (200), (220),

(311), (222), (400), (331) and (420) are associated with the cubic lattice of pure

CeO2 and is in good agreement with JCPDS DATA (34-0394). No identifiable

diffraction peaks are observed for the evidence of Ce2O3 crystallite phase in XRD

pattern and it shows the single phase nature of ceria nanoparticles. The XRD pattern

of annealed samples shows the increased intensity with decreased FWHM which

confirms the improved crystallinity. The annealing temperature strongly affects the

structural parameters like crystallite size and lattice constant as shown in Fig.3.2 a-c

and table 1. Annealing temperature increases the crystallite size from 11.9 nm to

52.7 nm. It must be noted that the crystallite size increases gradually with increasing

annealing temperature and crystal growth becomes sharp at temperature above

56.2610

59.1246

69.4298

76.7669

0.3897

0.7793

0.7793

0.792

3 1 1

2 2 2

4 0 0

3 3 1

24.1

12.2

12.9

13.3

0.93

3.47

2.68

2.31

0.81

1.53

1.25

1.11

0.1348

0.2617

0.2368

0.2251

0.92511

0.90611

0.84264

5.424

5.412

5.418

5.407

Annealed

900 oC

28.6819

33.2149

47.5863

56.4383

59.1787

69.5008

76.7904

79.1576

0.1624

0.1624

0.1624

0.1584

0.1188

0.1584

0.1584

0.1188

1 1 1

2 0 0

2 2 0

3 1 1

2 2 2

4 0 0

3 3 1

4 2 0

52.7

53.3

55.8

59.4

80.2

63.7

66.8

90.5

0.37

0.32

0.20

0.15

0.08

0.11

0.09

0.05

0.71

0.61

0.41

0.33

0.23

0.25

0.22

0.16

0.0812

0.0752

0.0618

0.0547

0.0398

0.0481

0.0450

0.0330

1.17205

1.05875

1.05011

0.93234

0.85124

0.83948

0.99289

1.10319

5.390

5.394

5.404

5.403

5.404

5.405

5.406

5.406

174

500oC, it may be assumed that the particles grow mainly as a result of an interfacial

reaction. The lattice constant of the samples are slightly higher compare to the bulk

counter parts due to its increased oxygen vacancies. The influence of particle size on

lattice parameter also noticed from XRD pattern.

The particle size increases, the value of lattice parameter decreases as shown

in Fig. 3.2a. The texture coefficient clearly indicates that the samples are highly

oriented in (111) direction. Straight line of ln (D) vs 1/T is plotted in Fig. 3.2d

according to the Scott equation, given below on the assumption that the

nanocrystallite growth is homogeneous, which approximately describes the

nanocrystallite growth during annealing ,

where, D is the crystalline size, C is the constant, E is the activation energy

for nanocrystallite growth, R is the ideal gas constant and T is the absolute

temperature of heat treatment. The activation energy of CeO2 nanoparticles during

annealing is found to be 1.004 eV.

Figure 3.2 Structural parameters of CeO2 nanoparticles

)1(exp

RTECD

175

Figure 3.3 SEM images of CeO2 nanoparticles

3.2 SEM Analysis

Fig. 3.3a shows the photograph of the as-prepared sample. SEM images of

as-prepared sample show the agglomeration of small crystallites and are attributed to

uncontrolled coagulation during precipitation at higher temperature. Small

crystallites are clinging together to form a large agglomerated spheroidal structure.

Annealing temperature improves particle size from 10 to 50 nm due to compact of

small granules joined together to form agglomeration of large granules as shown in

Fig.3.3 b-d in accordance with XRD results.

3.3 PL studies

RTPL spectra of Cerium oxide nanoparticles measured using 325 nm

excitation wavelength is shown in Fig. 3.4a-c. It exhibits strong blue emission with a

photoluminescence peak at 425 nm and relative weak green emission bands at 466

nm. The investigation showed that the emission bands ranging from 400-500 nm for

cerium oxide samples are attributed to the hopping from different levels of the range

from Ce 4f and O 2p band. The strong emission of the Cerium oxide samples at 466

nm is related to the abundant defects like dislocations, which are helpful for fast

oxygen transportation [9]. The defects energy levels between Ce 4f and O 2p are

dependent on the temperature and density of defects in the crystal. The annealed

(a (b

(c (d

176

samples show the strong and sharp emission bands at 425 nm in the blue visible

region.

Fig. 3.4 PL spectra of CeO2 nanoparticles

3.4 Electrical Properties

The Electrical conductivity of the prepared samples are calculted from the

following equation,

)2(/

CmS

Alx

VI

Where, I is the Current, V is the Applied Voltage, l is the thickness and A is

the Cross sectional area of the sample. In order to investigate the rectifying behavior

of the samples at different temperature, I-V characteristics are obtained by

connecting Keithley electrometer to thetwo probe setup.Then the current drop across

the sample for constant voltage is measured for different temperatures 30-200 oC. At

room temperature, CeO2 is nonconductive.

As the temperature increases, it becomes conductive and the electrical

conductivity σ depends strongly on the temperature. I-V characteristics of as-

prepared samples show sharp decrease of conductivity with the increase of

temperature upto 100 oC, that may be attributed to the presence of un eavoprated

precursor solvents and then slight decreases upto 200 oC. The annealed samples

show the slight decrease of conductivity upto 160 oC and sharp increase upto

177

Figure 3.5 I-V Characteristics of CeO2 nanoparticles

200 oC as shown in Fig. 3.5a-d. The conductivity is calculated using above formula

and the values are listed in table 2. The conductivity is found to be in the range

2.76X10-7 - 8.76X10-12 S/Cm. Fig. 4.5e shows the variation of ln (ρ) with

temperature for the prepared samples. It indicates the negative temperature

dependence of resistivity for as-prepared samples, where as annealed samples

indicate the positive temperature dependence of resistivity [7]. The activation energy

(Ea) is calculated using the following resistivity relation,

)3(exp

KTEa

o

Where, ρ is the resistivity of cerium oxide nanoparticles, is the pre-

exponential factor, Ea is the activation energy, K is the Boltzmann constant and T is

the absolute temperature. The activation energy values for cerium oxide

178

nanoparticles are calculated from the slop of the Arrhenius plot over the entire

temperature range as shown in Figure. The calculated activation energy is found to

be 0.984 eV according to XRD pattern. This value is in good agreement with the

values reported earlier.

Table 2. Electrical conductivity of cerium oxide nanoparticles

Conductivity (S/Cm) Temperature

(oC) C asp (X10-7) C A450 (X 10-10) C A900 (X10-11)

30 2.76425 7.46061 2.59054

40 2.47024 3.91858 3.92332

50 2.86441 0.46858 1.25131

60 2.49581 0.16504 0.81367

70 2.07096 0.08295 0.46885

80 1.51152 0.01896 0.39679

90 1.01162 0.04982 0.3605

100 0.49832 0.10437 0.34602

110 0.42625 0.19725 0.42526

120 0.38558 0.44119 0.45333

130 0.35462 0.86374 0.51049

140 0.3299 1.67356 0.66615

150 0.30241 2.69818 0.87671

160 0.28234 4.03346 1.34181

170 0.2603 6.15395 2.19979

180 0.23497 13.5364 6.28464

190 0.22778 37.4777 12.2985

200 0.23776 94.3789 21.0725

4. Conclusion

Nanocrystalline dispersed and uniform sized cerium oxide nanoparticles are successfully synthesized by a simple chemical precipitation method. From the results obtained it has been concluded that the selected material for the study has potential are several of research. Besides, the following conclusions are obtained.

179

PL spectra reveal the presence of blue emission in the visible region. XRD pattern confirms the single phase cubic fluorite structure with preferred orientation along (111) reflection. Annealing temperature increases the crystallite size upto 50 nm at 900oC.

Influence of particle size decreases the lattice constant. SEM images show the formation of large agglomerated spheroidal structure with an average particle size 10-50 nm. Annealing temperature improves the particle size and the agglomeration.

The calculated conductivity is in the range 2.76X10-7-8.76X10-12 S/Cm. The activation is energy calculated as 0.984 eV. Based on these results, it has been concluded that the annealing temperature strongly affects the surface, structure, electrical conductivity and oxidation states of cerium oxide nanoparticles.

References

1. I.R. Larramendi, N. Ortiz-Vitoriano, B. Acebedo, D.J. Aberasturi, I.G. Muro, A. Arango, E. Rodriguez-Castellon, J.I.R. Larramendi, T. Rojo, Pr-doped ceria nanoparticles as intermediate temperature ionic conductors, International Journal of Hydrogen Energy 36 (2011) 10981–10990.

2. N.K. Renuka, Structural characteristics of quantum-size ceria nano particles synthesized via simple ammonia precipitation, Journal of Alloys and Compounds 513 (2012) 230–235.

3. S. Wang, W. Wang, J. Zuo, Y. Qian, Study of Raman spectrum of CeO2 nanometer thin films, Materials Chemistry and Physics 68 (2001) 246–248.

4. J.R. Vargas-Garcia, L. Beltran-Romero, R. Tu, T. Goto, Highly (1 0 0)-oriented CeO2 films prepared on amorphous substrates by laser chemical vapor deposition, Thin Solid Films 519 (2010) 1–4.

5. F. Zhang, S.W. Chan, J.E. Spanier, E. Apak, Q. Jin, R.D. Robinson, I.P. Herman, Cerium oxide nanoparticles: size-selective formation and structure analysis, Applied Physics Letters 80 (2002) 127–129.

6. A. Kumar, S. Babu, A.S. Karakoti, A. Schulte, S. Seal, Luminescence properties of Europium-doped cerium oxide nanoparticles: Role of vacancy and oxidation states, Langmuir 25 (2009) 10998-11007.

7. T. Ristoiu, T. Petrisor Jr., M. Gabor, S. Rada, F. Popa, L. Ciontea, T. Petrisor, Electrical properties of Ceria/carbonate composites, Journal of Alloys and Compounds 532 (2012) 109-113.

180

SYNTHESIS AND CHARACTERIZATION OF PURE AND L-ALANINE

DOPED AMMONIUM DIHYDROGEN PHOSPHATE(ADP)

R. Deepika, P. Meena* Department of Physics, PSGR Krishnammal College for Women, Coimbatore, India.

Abstract: pure and Doped (with L-alanine) Ammonium dihydrogen phosphate

(ADP) crystals were grown by slow evaporation method at room temperature. The

grown crystals were subjected to powder X–ray diffraction studies to study their

structural characteristics. addition of amino acid is found to improve the

crystalquality, yielding highly transparent crystals with well-defined features. The

values of the lattice parameters were determined by single crystal X-ray

diffractionThe vibrational frequencies of the grown crystals were identified using

FT-IR spectral analysis.The UV-visible study confirms the wide optical

transmittance window for all doped crystals which is vital for optoelectronics

applications. The transmission data has been used to evaluate the optical band gap

and optical conductivity.

Key words:ADP,AMINO ACID-L-ALANINE,FTIR,UV XRD.

1. INTRODUCTION

Ammonium dihydrogen phosphate (NH4H2PO4) crystals attract much interest

because of their unique non– linear optical, dielectric, piezoelectric and

antiferroelectric properties and their variety of uses such as electro-optic modulators,

harmonic generators and parametric generators [1-3]. Several research works have

been carried out on pure and doped ADP crystals [1-5].With an aim to find new

useful materials for academic and industrial use, an attempt has been made to modify

the ADP crystals by adding 1 mole % by weight of L-ALANINEin the mother

solution of ADP.

2. EXPERIMENTAL PROCEDURE

2.1. Crystal Growth:

Pure ADP and L-alanine (AR grade) doped ADP crystals were grown using a

good quality seed crystal at room temperature by the solvent evaporation method.

For the preparation of seed crystals, the supersaturated solution of ADP was

181

prepared first and then kept in a petri dish coveredwithperforated polyethylene to

allow the growth of seed crystals within 4 - 5 days. The purity of the crystals was

improved by successive recrystallization process. The period taken for the growth of

bigger size crystals is 25 - 30 days. The grown crystalswere found to be colorless

and transparent. The crystals were characterized using powder XRD technique, FTIR

and UV-VIS-NIR spectroscopic techniques.

2.2. CHARACTERIZATION:

The grown crystals were subjected to powder X–ray diffraction studies to

study their structural characteristics. The addition of amino acid is found to improve

the crystalquality, yielding highly transparent crystals with well-defined

features.Fourier transform infrared (FTIR) spectral analysis was performed to

identify the presence of various functional groups in the crystalsin the range of 4000-

400 cm -1.The UV–Visible–NIR spectral analysis was carried out to confirm the

improvement in the transparency of the ADP crystal on addingL-alanine. The optical

properties of the grown crystals were studied using Shimadzu UV-1601 visible

spectrometer in the wavelength region 200-1100 nm.

3. RESULT AND DISCUSSION

3.1. XRD Analysis:

The crystallographic structure and lattice parameters of the ADP single

crystalsgrown by the slowevaporation methodwere determined from the X-ray

diffraction pattern obtained employing X-ray diffractometer. The diffraction peaks of

the XRD patterns shown in Figure 2 could be indexed as those of the ADP with

tetragonal structure (JCPDS Card No.37-1479). The XRD peaks were indexed and

crystallographic lattice parameters were determined by powder-X software. The

determined lattice parameters are a = 7.502 °A and c = 7.554 °A having space group

The lattice parameters are in good agreement with the reported values. The.42ܫܫ

obtained spectrum is shown in Fig. 1. The prominent peaks of pure ADP are (101),

182

(200), (211), (220), (301) and (400).The obtained peaks for the doped(L-alanine)

crystals are similar to that of the pure ADP crystalwith a slight variation in the

intensity.X-ray powder diffraction patterns of pure ADP and doped ADP crystals are

found to be identical. As seen in the figure, no additional peaks are present in the

XRD spectra of doped ADP crystals, showing the absence of any additional phases

due to doping.

Fig. 1. Powder XRD spectra of (a) pure ADP crystal and L-alanine doped

ADP crystal

3.2. FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR):

The influence of additives used in this work on the vibration frequencies of

functional groups of pure ADP crystal has been identified by FTIR spectroscopy.The

FTIR spectra were recorded in the regions 400–4000cm−1 using a Perkin Elmer FTIR

Spectrum RXI spectrometer by the KBr pellet technique. Fig.2 shows the FTIR

spectra of Pure and L-Alanine doped ADP crystal. The functional groups of pure

ADP crystals involved in vibration frequency have been identified using FTIR

spectroscopy. The peak at 589.92 cm-1is due to the PO4-vibrations in ADP

crystal.The peaks between 613.39 and 866.08cm-1 are due to the P-O-H Vibration

and P-O-H Stretching.The peaks between 1079.22cm-1and 1090.79cm-1are also due

to the P-O-H Vibration and P-O-H Stretching.The peaks between 1220.99cm-1and

1268.25cm-1 are due to combination of the asymmetric stretching vibration of PO4

with the latticeP-O stretching vibration.The peak at 1408.10cm-1is attributed to the

Bending vibration of ammonium,and bendingand stretching of NH4.The peaks

183

between 1562.41and1747.58cm-1are due to O-H Bending vibration. The peaks

between 3002.33cm-1and 3209.69 cm-1 are due to O-H Stretchingand N-H

Vibration.These support the presence of L-Alanine in the lattice of ADP.

Fig 2.FTIR spectra of Pure and L-alanine doped ADP crystals

Table 1.1 shows the FTIR spectra of Pure and L-alanine doped ADP crystal.

Pure

ADP

Doped ADP Band assignments

3209.69-

3024.51

3002.33 O-H Stretching,

P-OH Stretching,

N-H Vibration

1562.41 1747.58-

1598.09

O-H Bending vibration,

O-H Bending water

1408.10 _ Bending vibration of

ammonium ,Bending

stretching of NH4

1268.25 1266.32-

1220.99

Combination of the

asymmetric,stretching

vibration of PO4 with

lattice,P-O stretching

vibration

1079.22 1090.79 P-O-H vibration,P-O-H

stretching

184

866.08-

663.54

613.39 P-O-H vibration,P-O-H

stretching

598.92 _ PO4 vibrations.

3.3. OPTICAL STUDIES UV-VIS-NIR SPECTROSCOPY:

Optical transmission spectra were recorded for the samples obtained from

pure as well as additive added crystals grown by the slow evaporationmethod. The

spectra were recorded in the wavelength region from 200 to 2200 nm.

The UV–Vis spectra recorded for pure and additive added ADP crystals is

shown in Fig.3It is clear from the figure that the crystals have good transmission in

the entire visible and IR region.The optical transparency of the ADP crystal is

increased by the addition of L-alanine. It has also been observed that the cut off

wavelength is the same for pure and additive added ADP crystals.The addition of the

amino acid dopants in the optimum conditions to the solution is found to suppress

the inclusions and improve the quality of the crystal with higher transparency

.

Figure 3.Transmittance spectrum of ADP single crystal and doped ADP crystal

Table .1 Band gap energy

SAMPLE DIRECT BANDGAP ENERGY

ADP 3.7ev

ADP+ L-ALANINE 3.8ev

185

Fig-4 Direct bandgap energy for ADP.

Fig-5 Direct bandgap energy for ADP+L-ALANINE

4. CONCLUSION

Good quality transparent single crystals of ammonium dihydrogen phosphate

(ADP) (NH4 H2 PO4) have been grown by the slow evaporation method at room

temperature. The X-ray diffraction pattern of ADP showed that the prepared crystals

possess tetragonal structure with lattice parameters in good agreement with the

reported data (JCPDS Card No.37-1479). The functional groups of ADP crystals

involved in vibration frequency were identified using FTIR.The optical bandgap

values determined from the optical transmittance study of the ADP crystals and

doped ADP give direct bandgap values of 3.7 eV and 3.8 eV respectively. The

addition of L-alanineis found to help the growth of high quality large size single

crystals at a faster growth rate.

REFERENCES

[1] S.R.Marder, B.G.Tiemann, J.W.Perry, et.al., Materials for Non-linear optical chemical perspectives (American Chemical Society, Washington, 1991).

[2] P.Santhana Raghavan and P.Ramaswamy, Recent Trends in Cryst. Growth (Pinsa 68, New Delhi, 2002).

[3] A.Anne Assencia and C.Mahadevan, Bull of Mater. Sci., 28, 2005, 415. [4] V.Ya.Gayvoronsky, M.A.Kopylovsky, V.O.Yatsyna, A.S.Popov,

A.v.Kosinova, I.M.Pritula, Functional Mater., 19, 2012, 54. [5] J.Zhao, M.Ikezawa, A.V.Ferderov, Y.Masumoto, J.Lumin., 525, 2000, 87.

186

Novel synthesis route of γ- glycine single crystal in the presence of

2-aminopyridine potassium chloride for optoelectronic applications

R. Srineevasan

P.G & Research Department of Physics, Government Arts

College,Tiruvannamalai,606603,India

Abstract

In this research paper, an overview of polymorph γ-form glycine single crystal

crystallization in the presence of 2-aminopyridine potassium chloride as an additive

at an anambient temperature by slow evaporation solution growth technique (SEST)

has been presented. FTIR and NMR studies confirm the presence of functional

groups in the grown crystal. In the UV–Visible NIR optical absorption spectral

studies from 200 nm to 900 nm, the observed 0% absorption with lower cutoff wave

length at 240 nm enables the calculation of band gap value. Powder XRD study

confirms crystalline nature of the grown γ-glycine crystal. The single crystal XRD

study shows that the grown crystal possesses hexagonal structure and belongs to

space group P31 with the cell parameters a=7.09 Å; b=7.09; c=5.52 Å; α = β = 90˚;

and γ = 120˚. Thermal studies have been carried out to identify the enhanced thermal

stability and decomposition temperature of the grown sample. Dielectric studies of as

grown γ-glycine crystal exhibit low dielectric constant at higher frequencies, which

is most essential parameters for nonlinear optical applications. SHG efficiency of the

grown crystal was confirmed by the Kurtz powder technique using Nd:YAG laser

and found 1.6 times greater than that of inorganic standard potassium dihydrogen

phosphate.

Keywords: Slow evaporation, Single crystal, NMR spectrum, TGA-DTA, SHG

efficiency.

1. Introduction

Highly polarizable conjugated system of organic molecule possesses

non-centro symmetry structure. The inorganic molecule (anion), linking through

hydrogen bond with organic molecule (cation) yields strong mechanical and high

thermal stability [1,2]. Molecular charge transfer induced in semiorganic complex by

delocalized π electron, such that moving between electron donor and electron

acceptor which are in opposite sides of the molecules [3,4]. In the base acid

187

interaction of organic and inorganic molecules, there is a high polarizable cation

derived from aromatic nitro systems, linked to the polarizable anion of inorganic

molecules through hydrogen bond network yields a noncentrosymmetric structural

systems and this hydrogen bonding energy between organic and inorganic molecules

made the dipole moment in parallel fashion ensures the increase of second harmonic

generation activity [5]. The structures of 2-aminopyridine complexes have already

been studied by Chao and his co-workers [6]. In recent years metal organic

complexes have been played reasonable attention in advancement of technology

[2,7]. Growth of 2-aminopyridine complex crystals is widely used in the

rapid advancement in technology, such as ultra-fast phenomena, optical

communication and optical storage devices , frequency doublers and optical

modulators [8]. Optical properties of 2-aminopyridine complexes and their suitability

for optoelectronic devices have been reported [9-14]. Metal organic nonlinear optical

crystals possess good second harmonic generation efficiency, hence rich demand in

optical storage devices, color display units and optical communication systems [7].

Recent research focus is on designing of new materials capable of attaining SHG

processes by strong interaction with an oscillating field of light. Amino acids with

ionic salt complex crystals have been investigated and recognized as materials

having good nonlinear optical properties [1,3,15-17]. In this present work, synthesis

and crystallization of glycine into γ-form glycine in the presence of aqueous solution

2-aminopyridine potassium chloride and their suitability for device fabrication with

various enhanced physical properties are reported.

2. Experimental Procedure

2.1 Material synthesis

The title compound was synthesized by taking analytical grade glycine,

2-aminopyridine and potassium chloride in the stoichiometric ratio (1:1:1) with

Millipore water of resistivity 18.2 mega-ohm.cm-1 as a solvent.

In this synthesis, protonation of nitrogen in pyridine ring facilitates hydrogen

bonding interaction between potassium chloride and glycine such that 2-

aminopyridine is linked to the metal K+ ion through pyridine ring nitrogen, rather

than amino group nitrogen leaving (Cl)- ion [18].

C5 H6 N2 + KCl + NH2 CH2 COOH → [(K+) + C5H6N2 COOCH2 NH2 (Cl)–]

188

[(2-aminopyridine) + (potassium chloride) + (glycine)]→ [(γ-glycine crystal)]

Amino group hydrogen in 2-aminopyridine coordinates through hydrogen bond

with carboxylic groups of monoprotonated glycinium ion. Stacking of γ- glycine

crystal one over the other is shown in Figure 2.1.

N

N C

H

O

C

H

H

N

H

H

N

N C

H

O

C

H

H

N

H

H

K

K

Cl

Hydrogen Bond

Figure 2.1 Scheme of as grown γ-glycine crystal

2.2 Solubility study of γ-glycine in the presence of 2-aminopyridine potassium

chloride

Solubility is an important parameter, which dictates the crystal growth

process. The solubilities of the title compound in aqueous medium were estimated in

the temperature range between 30 and 50˚C. Neither a flat nor a steep solubility

curve and less viscous solution enabling the faster transfer of the growth units by

diffusion of the title compound, enables the growth of bulk crystals from solution.

Variations in solubility at different temperatures is plotted in Figure 2.2 The

moderate variations in solubility indicate the reasonable growth rate of title

compound along all crystallographic directions.

25 30 35 40 45 50

2

4

6

8

10

12

14

16

18

20

2-APKCG

Solu

bilit

y (g

/100

ml)

Temperature ( 0C) Figure 2.2 Solubility curve of title compound at different temperatures

189

2.3 Crystal Growth

The prepared mother solution was stirred vigorously for 4h using magnetic

stirrer. High degree of purification of synthesized salt was achieved by successive

recrystallization process. Synthesized saturated solution was filtered using filter

paper of micron pore size. The filtered solution was pored in different petri dishes

and covered with porous paper for slow evaporation. After a time span of 15 days,

quality crystals of average size 13mm x 12mm x 3mm were harvested. The

as grown crystal is shown in figure2.3.

Figure 2.3 As- grown γ-glycine crystal

3. Results and discussion

The as grown γ-glycine crystal was subjected to FTIR analysis using PERKIN

ELMER SPECTRUM RX1 Fourier Transform infrared spectrometer. 1H NMR and 13C NMR spectroscopic studies were done by a Bruker Advance III 500MHz

FTNMR spectrometer using D2O as solvent to identify the functional groups. The

transmission behavior was studied by using LAMBDA-35 UV-VIS

Spectrophotometer. Single crystal and powder XRD analysis were carried out on a

PHILIPS X PERT MPD system. TGA and DTA analysis were carried out using

NETZSCA STA 409 instrument at a heating rate of 20°C min-1 from ambient to

500°C. Dielectric studies were carried out by using HIOKI 3532 HiTESTER LCR

meter. The NLO efficiency of the grown crystal was tested by KURTZ powder

technique using Nd: YAG laser of wavelength 1064 nm.

3.1 Fourier Transform Infrared (FTIR) analysis

The as grown γ-glycine crystal was subjected to FTIR analysis by KBr

pellet technique in the wavelength between 4000 and 400 cm-1. The recorded

190

absorption spectrum of title compound confirms the presence of various functional

groups and their frequency assignments are shown in figure 3.1. The doublet

frequency 928.06 and 888.46 cm-1 clearly shows the γ- glycine formation [19]. The

vibrational frequencies are assigned with structure as shown in Table 1.

Table 3.1. Frequency of the vibrations and their assignment of as grown γ-

glycine crystal

3105

.77

2887

.67

2604

.48

2360

.74

2171

.48

1586

.84

1492

.95

1393

.84

1327

.82

1126

.21

1041

.67

928.

0688

8.46

683.

10

502.

8745

2.34

412.

37

500100015002000250030003500Wavenumber cm-1

2030

4050

6070

8090

100

Tran

smitt

ance

[%]

Fig 3.1 FTIR spectrum of the grown γ-glycine crystal

Frequency in wave number

(cm-1)

Assignment of vibration

3105.77 NH3+ Stretching

2887, 2604 Aliphatic CH2 Stretching

2171.48 NH3+ Stretching

1586.84 NH2+ Bending

1492.95 COO - Symmetric Stretching

1327.82 CH2 Twisting

1126.21 NH2+Rocking

1041.67 C-N Stretching

928.06 CH2 Rocking

888.46 C-C-N Symmetric Stretching

683.10 COO - Bending

502.87 COO - Rocking

191

3.2 NMR spectrum

1H NMR and 13C NMR analysis of the as-grown γ-glycine crystal were

shown in figure 3.2 & 3.3. 1H NMR spectrum of as-grown γ-glycine crystal showed

multiple peak signals at δ 3.461 to 3.445 ppm (quartet or triplet) corresponds to

protons of methylene group (CH2) and peak at δ 4.678 ppm due to amino group

protons (NH2). 13C NMR spectrum of as-grown γ-glycine crystal showed peaks at δ

41.429 ppm and δ 172.41 ppm corresponding to methylene carbons and carbonyl

carbon respectively. All the above results support the true chemical reactions in the

formation of the γ-glycine crystal.

Figure 3.2 1H NMR of γ-glycine crystal

Figure 3.3 13C NMR of γ-glycine crystal

192

3.3 UV- Visible spectral analysis

The optical properties of the crystals are mainly depends on the interaction

between crystal and components of electric and magnetic fields of the

electromagnetic wave. UV-Visible absorption spectrum of the grown crystal

recorded in the wave length range 200-900 nm was shown in figure 3.4. The

grown crystal has good transmission (100%) in UV, Visible and IR region. This

highest transmission percentage (100%) clearly shows the intrinsic property of

amino acid and their defect less nature of the grown γ-glycine crystal [20]. The

absorption spectrum shows that the grown crystal has lower cut off wavelength at

240 nm and this characteristic is most favorable for nonlinear optical materials.

Lower cut off wavelength value of the γ-glycine crystal (240nm) is compared

with Glycine potassium chloride (GPC), Serine sodium chloride (SSC), Bis

glycine Maleate, Pure Glycine, Glycine potassium sulphate (GPS), and Glycine

picrate as shown in Table 2. This observed decreasing lower cutoff wavelength

value of the as grown crystal is due to the addition of 2-aminopyridinium

potassium chloride. Hence the lower cut off wave length of as grown crystal can

be suitably used for optoelectronic application in the UV, Visible and IR range.

Table 3.2

*present work

Crystals Name Cutoff wave

length(nm)

GPC 295

SSC 300

Bis glycine

Maleate

330

Pure Glycine 346

GPS 384

Glycine picrate 450

γ- glycine crystal* 240

193

200 300 400 500 600 700 800 900

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Abs

orba

nce

(a.u

)

Wavenumber (nm)

Figure 3.4 UV-Visible absorption spectrum of grown crystal of γ-glycine

Since optical properties of the crystals are governed by the interaction

between the crystal and the electric and magnetic fields of the electromagnetic

wave, transmittance (T) was used to calculate the absorption coefficient (α) using

the formula:

1 2 3 4 5 6 7

0

50

100

150

200

250

300

Eg=5.5 ev

(alp

ha.h

v)2 .e

v2 .mm

2

hv ev

Figure 3.5 Plot of hυ versus (αhυ)2 of as grown γ-glycine crystal

Where t is the thickness of the sample. The optical band gap (Eg) was evaluated from

the transmission spectra and the optical absorption coefficient (α) near the absorption

edge is given by [21].

αhυ=A(hυ-Eg)1/2

194

where A= constant, Eg= the optical band gap, h= the Plank’s constant and υ= the

frequency of the incident photons. The graph drawn between hυ (E=hυ) and (αhυ)2

is used to estimate the direct band gap value of the grown crystal as shown in

figure3.5. The band gap of γ-glycine single crystal was estimated by extrapolating

the linear portion near the onset of absorption edge to the E=hυ axis. From the Figure

3.5, the optical band gap value is calculated to be 5.5 eV. The wide band gap of the

as grown γ-glycine crystal confirms the 100% transmittance in the UV-vis-NIR

region and less defect concentration of the grown crystal [22]. The observed lower

cutoff wavelength 240 nm of the as grown γ-glycine due to the addition of 2-

aminopyridinium potassium chloride leads to an increase in the band gap of the

compound 5.5 eV.

3.4 Powder XRD studies

The grown γ-glycine crystal crushed to a uniform powder and subjected to

powder x-ray diffractrometer with CuKα (λ=1.540598 Å) radiations for structural

analysis study. The powder form sample was scanned over the range 10-45˚ at the

rate of 2˚/min. The indexed powder XRD pattern of grown crystal is shown in figure

6. Peaks in the XRD without any broadening confirm that the grown sample is higher

order of crystalline nature.

1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

(011

)(0

12)

(001

)(0

02)

(010

)

(101

)

(100

)(0

31)

(110

)

(120

) (200

)(1

11) (2

01)

(002

)

(201

)

(102

)

(112

)

(210

)(0

02)

(112

)

(211

)

(300

)

Inte

nsity

(a.u

)

D i f f r a c t io n a n g le ,2 ( d e g )

2 -A P K C G

Fig 3.6. Powder XRD pattern of as grown crystal γ-glycine

195

3.5 Single crystal XRD analysis

Single crystal X-ray diffraction analysis confirms the hexagonal structure

of the γ-glycine crystal with space group P31. The unit cell parameters of the

grown γ-glycine are a = 7.09Å; b = 7.09Å; c = 5.52Å; α = β = 90˚; γ = 120˚ and

volume of the unit cell was found to be 278 Å3. These values are in-line with the

literature values [23-25]. Further, it is evident that the presence of 2-aminopyridine

potassium chloride in the aqueous solution, without enter into the grown crystal

lattice, yields the polymorph form γ-glycine, as a physical change.

3.6 Thenarmal analysis

Thermo gravimetric (TG) and Differential thermal analysis (DTA) gives

information regarding phase transition, water of crystallization and different stages

of decomposition of the crystal. Samples of γ-glycine crystals were weighed in an

Al2O3 crucible with a microprocessor driven temperature control. TGA and DTA

curves of grown crystals were recorded in nitrogen atmosphere between ambient

temperature to 500˚C shown in Figure 3.7. There is no weight loss up to 216.6˚C

indicating that there is no inclusion of solvent (water) in the crystal lattice. The

thermogram reveals that the major weight loss (42.4%) starts at 216.6˚C and

continues up to 484.4˚C with 1.255mg (57.6%) as residue. The nature of weight loss

indicates the decomposition of the material. Below 484.4˚C no weight loss was

observed.

Temp Cel500.0400.0300.0200.0100.0

DTA

uV

40.00

30.00

20.00

10.00

0.00

-10.00

-20.00

TG m

g

2.800

2.600

2.400

2.200

2.000

1.800

1.600

1.400

1.200

TG %

100.0

95.0

90.0

85.0

80.0

75.0

70.0

65.0

60.0

55.0

50.0

45.0

216.6Cel2.838mg

484.4Cel1.255mg

1.583mg

484.4Cel2.838mg

55.4%

609uV.s/mg

Fig 3.7. TGA& DTA graph of as grown γ-glycine crystal

196

DTA curve shows that the decomposition point of as grown γ-glycine crystal is

270˚C. This decomposition point was compared with the decomposition point of

pure γ-glycine crystal (246˚C) and γ-glycine synthesizes in the presence of different

additives are shown in Table 3.3.

Table 3.3

γ-glycine crystal Decomposition point

In the presence of CoCl 116.86 ˚C [29]

In the presence of CaCl2 265 ˚C [30]

In the presence of AgNO3 208 ˚C [31]

In the presence of Li NO3 195 ˚C [32]

In the presence of LiBr 200 ˚C [33]

In the presence of NH3 145.7 ˚C [34]

In the presence of NaNO3 256 ˚C [35]

In the presence of MgCl2 213 ˚C [36]

In the presence of KCl 170 ˚C [37]

In the presence of KF 259 ˚C [25]

In the presence of HF 240 ˚C [38]

In the presence of H3PO3 &

In the presence of H3PO3 + Urea

51 ˚C [39]

155 ˚C [39]

In the presence of

C5H6N2+KCl**

270 ˚C

** present work

3.7 Dielectric studies

Cut and polished samples of dimensions 11.92 x 8.99 x 3.51mm3 were used

for dielectric measurements. Graphite was applied on opposite sides of the sample

and the dielectric placed between two copper electrodes and thus parallel plate

capacitor was formed. The capacitance of the crystalline sample was measured for

various frequencies in the range 500HZ to 5MHZ at different temperatures. The

dielectric constant was calculated using the formula, Ɛr= Ct/ƐOA Where C, is the

capacitance; t, thickness of the sample; Ɛo, the permittivity of the free sample and A,

197

the area of cross section. Variation of dielectric constant with frequency for the as-

grown crystal of γ-glycine at different temperatures is shown in fig 3.8.The dielectric

constant has higher value at low frequency region and then decreases with the

increase in the frequency. The Ɛr value reached the least value of about 25 at the

applied frequency of 2.5 KHZ and the value remains constant for further frequency.

A similar trend was observed for all the recorded temperatures. Among the all four

polarizations, electronic and space charge polarizations are predominant in the low-

frequency region. The characteristic of low dielectric constant at higher frequency

suggests that the sample possesses an improved optical quality with lesser defects

and this parameter is most important for nonlinear optical materials and their

applications.

2 4 6 8

0

1000

2000

3000

4000

5000

6000

7000

Die

lect

ric C

onst

ant

r

Log f

40o C 45o C 50o C 55o C 60o C

Fig 3.8. Dielectric behavior of γ-glycine crystal

3.8 NLO studies

In order to confirm the NLO property, powdered sample of grown crystal

was subjected to KURTZ and PERRY powder technique, which is a powerful tool

for initial screening of the materials for second harmonic generation (SHG) [26]. The

beam of wave length λ =1064 nm from Q-switched Nd:YAG laser was made to fall

normally on the prepared powdered sample of grown γ-glycine crystal , which was

packed between two transparent glass slides. Suitable solution (CuSO4) was used to

absorb the transmitted beam and the optical second harmonic signal was detected by

a photomultiplier and displayed on CRO. Here powder form of KDP crystal of

identical size to grown γ-glycine crystal powder particles were used as standard in

the SHG measurement.The SHG behavior was confirmed from the emission of

198

bright green radiation (532nm) by the sample. The measured amplitude of second

harmonic green light for as grown γ-glycine crystal was 14.9mJ as against 8.8mJ of

KDP and 8.9mJ of UREA.

Table 3.4 Comparision of SHG efficiency of γ-glycine crystals

γ-glycine crystal # SHG efficiency

In the presence of NaF 1.3[27]

In the presence of NaOH 1.4[27]

In the presence of NaCl/KCl 1.5[28]

In the presence of

NaCH2COOH

1.2[28]

*In the presence of

C5H6N2+KCl

1.65

*Present work, #With reference to KDP

The result shows powder SHG efficiency of as grown γ-glycine crystal is

about 1.65 times that of KDP and 1.63 times of UREA. This value is relatively high

when compared to the SHG values reported for γ-glycine crystals grown with other

additives and comparision is given in Table 3.4. This enhanced lasing performance

of as grown γ-glycine crystal is due to the additive influence of 2-aminopyridinium

potassium chloride. The good second harmonic generation efficiency of as grown γ-

glycine crystal in the presence of 2-aminopyridine potassium chloride attests, that the

grown crystal is a potential candidate for nonlinear optical applications.

5. Conclusion

We have successfully grown polymorph γ-form of glycine single crystals by

slow evaporation solution growth technique at ambient temperature. FTIR & NMR

spectral studies confirm that 2-aminopyridine potassium chloride not entered into the

crystal structure, but they inhibit the growth of polymorph form γ-glycine. UV –

Visible spectral studies show that it has the wide range of transmission from 240nm

to 900nm with cut off wave length 240 nm and the observed high transmittance

percentage (100%) from 240 nm clearly indicates that the grown crystal possessing

good optical transparency for second harmonic generation of Nd:YAG laser. Powder

199

and single crystal XRD studies reveal that the grown γ-glycine crystal is having

higher order of crystallinity. Thermal studies show the sample is thermally stable up

to 270°C and this makes the grown crystal’s suitability for possible application in

laser, where the material is required to with stand high temperatures. Dielectric

studies of grown crystal confirm the improved optical quality. NLO studies of the

grown sample show that the SHG efficiency is greater than KDP (1.65 times) and

Urea (1.63 times) crystals. The grown γ-glycine crystals in the presence of 2-

aminopyridine potassium chloride were possesing various enhanced properties such

as wide transparency range with 100% transmission, low dielectric constant value at

higher frequency and hence improved optical quality with lesser defects and elevated

decomposition temperature (270˚C) with greater SHG efficiency as that of KDP

suggest that the grown γ-glycine crystals in the presence of 2-aminopyridine

potassium chloride is a promising materials for optoelectronic applications.

Acknowledgements

The authors are would like to thank Professor Dr. R. Jayavel, Director,

Academic Research, Anna University, Chennai, for their constant support and

providing facilities to avail various characterization studies for crystals. One of the

author Dr. R. Srineevasan, is grateful to the University Grants Commission, India for

granting Minor project to carry out the research work.

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202

Structural and optical properties of zinc oxide/magnesium oxide (ZnO/MgO)

nanocomposites synthesized by the facile precipitation process

D. Siva a,, K. Anandan b a, Department of Physics, Shanmuga Industries Arts & Science College,

Thiruvannamailai – 606 601, Tamilnadu, India b Department of Physics, AMET University, Kanathur, Chennai – 603 112,

Tamilnadu, India

Tel.: +91-9597873334 a, +91-9940156552 b

Email id: siva00025@gmail.com a, anand.nanoscience@yahoo.com b

Abstract

Different solvents such as ethanol, ethanol-water and water mediated zinc

oxide/magnesium oxide (ZnO/MgO) nanocomposites have been successfully

synthesized by the facile precipitation process. The structure, purity, crystallite size

and the phase of the synthesized ZnO/MgO nanocomposites are confirmed by the

powder XRD patterns. The functional groups of the samples are confirmed by the

FTIR analysis. The optical properties of the prepared ZnO/MgO samples are

characterized by the UV-visible absorption and the PL emission spectroscopies. The

UV and PL studies are used to determine the band gap, impurity, material quality

and defect levels in the metal oxide nanocomposites.

Keywords: Nanocomposites; ZnO/MgO; Precipitation; Structural; Optical properties

1. Introduction

During*the last few years, synthesis of metal oxide nanocomposite materials

have been attracted considerable attention [1–5]. The metal oxides nanocomposites

are extremely important technological materials for use in optoelectronic and

photonic devices and as catalysts in chemical industries. In recent years, researchers

have focused more on the synthesis of nanocomposite of ZnO/ MgO due to their

application in advanced technologies. Various physicochemical techniques have

been employed to construct nano sized ZnO/MgO nanoparticles [6-17]. Several

techniques have been also developed to prepare nanocomposite of ZnO/MgO. This

nanocomposite has attracted much attention because it has a larger band gap than

ZnO [18-20]. However, most of the techniques need high temperatures and perform

under a costly inert atmosphere. Our goal in this research is to suggest an easy

203

method to synthesize zinc oxide/ magnesium oxide nanocomposite. Considering the

importance of luminescent materials in interdisciplinary materials science and future

optoelectronic applications, the present work is focused on the synthesis of zinc

oxide/magnesium oxide (ZnO/MgO) nanocomposites. They have attracted increasing

interest in fabricating nanostructures with the size and the optical properties could be

achieved by varying the solvents. With this motivation, ZnO/MgO nanocomposites

were prepared by simple precipitation process and their structural, size and optical

properties were studied. The as-synthesized samples are subjected to the different

characterization techniques such as the powder X-Ray Diffraction (XRD), the

Fourier Transform Infrared (FTIR), the Ultraviolet-visible (UV-vis) absorption and

the Photoluminescence (PL) analyzes.

2. Experimental procedure

2.1 Synthesis of ZnO/MgO nanocomposites

The preparation of zinc oxide/magnesium oxide nanocomposites using the

facile precipitation process. All the chemical reagents were commercial with AR

purity, and used directly without further purification. In a typical experiment, 0.1M

of zinc acetate dehydrate (Zn(CH3COO)2∙2H2O) and magnesium acetate tetrahydrate

(Mg(CH3COO)2∙4H2O) were dissolved in 100 ml ethanol. The precipitates were

obtained by the addition of 0.4 M of sodium hydroxide (NaOH) pellets to the above

solution, which was stirred for one hour. The resultant precipitate was filtered,

washed with distilled water and absolute ethanol to remove the impurities, and dried

at 120ºC for 15 hrs. Then, ash colored ZnO/MgO sample was obtained, when dried

sample was calcined at 450ºC for 2h. The same procedure was followed for the

preparation of ZnO/MgO in ethanol-water and water as solvents. The formation of

ZnO/MgO nanocomposites is given in the equation below:

Zn(CH3COO)22H2O

+ + 4NaOH Zn(OH)2/Mg(OH)2 + 4Na(CH3COO) + 6H2O

Mg(CH3COO)24H2O

-------------- (1)

Zn(OH)2/ Mg(OH)2 ZnO/MgO + 2H2O -------------- (2)

204

2.2 Characterization of synthesized nanocomposites

The characterization of metal oxide nanocomposites is essential for

understanding of their structural and optical properties. Due to the inherent

difficulties involved, the scientific experiments for the characterization should have

the ability for rapid collection of data of several parameters with good precision and

accuracy. The development of novel tools and instruments is one of the greater

challenges in nanotechnology. The different solvents mediated samples were

characterized by adopting various physico chemical methods namely XRD, FTIR,

UV-vis and PL. The prepared ZnO/MgO samples were characterized by using the

powder X-ray diffractometer, XPERT PRO with Cuk X-ray radiation (λ=0.15496

nm). The FTIR spectrum of the as-prepared sample was recorded, with a Bruker IFS

66 W Spectrometer using the KBr-pellet technique at a resolution of 4 cm–1 over the

range 4000–400 cm–1. The absorption study of the prepared samples has been carried

out using the Varian Cary 5E UV-vis spectrophotometer. The PL analysis of the

prepared samples was carried out, using the Fluoromax 4 spectrofluorometer, with

an Xe lamp as the excitation light source.

3. Results and discussion

X-ray diffraction (XRD) is a rapid analytical technique primarily used for the

phase identification of a crystalline material, and can provide information on unit

cell dimensions. This method uses a monochromatic source of X-rays and measures

the pattern of diffracted radiation, which is a result of the constructive interference

due to the crystalline structure of the powder. The crystallite size can be obtained

either by direct computer simulation of the X-ray diffraction pattern or from the Full

Width at Half Maximum (FWHM) of the diffraction peaks using the Debye-

Scherrer’s formula [21].

Fig. 1 XRD patterns of ZnO/MgO nanocomposites

prepared in (a) ethanol, (b) water-ethanol and (c)

water D=0.9λ/βcos

205

where,

λ - Wavelength of X-rays,

β - FWHM in radian,

- Peak angle.

Figure 1 (a-c) shows the XRD patterns of ZnO/MgO nanocomposits prepared

in ethanol, ethanol-water and water, respectively. All the peaks in the patterns could

be indexed to the ZnO/MgO nanocomposites. The existence of strong diffraction

peaks at 2 values located at 31.76º, 34.6º, 36.25º, 47.53º and 67.96º corresponding

to (100), (002), (101), (102) and (112) hexagonal wurtzite structure of ZnO crystal

planes (JCPDS Card No.79-205) and peaks at 42.9º, 47.6º , 62.28º and 74.65º,

corresponding to (001), (100), (102) and (110) cubic structure of MgO crystal planes

(JCPDS Card No. 45- 0946), respectively [22]. This fact indicates that the prepared

samples are not a single phase but a composite. Moreover, no impurity such as Zn

(CH3COO)2, Zn(OH)2, Mg(CH3COO)2 and Mg(OH)2 were detected. Peak

broadening indicates that the smaller crystallites size of the prepared ZnO/MgO

nanocomposites.

In any preparation of nanomaterials, the solvent is an important parameter for

determining the crystal size. In the present work, the organic mediated samples (Fig.

1(a-b)) show a slight broadening of peaks compared to the peaks of the aqueous

mediated sample, as shown in Fig.1 (c). This clearly reveals that using organic media

can produce fine particles. Using Scherrer’s formula, the average crystallite sizes of

the ZnO/MgO samples synthesized in ethanol, ethanol-water and water are found to

be 22, 23.91 and 25.82 nm, respectively. From the result it is concluded that the

ethanol mediated ZnO/MgO nanocomposites are most ultra-fine, owing to their best

dispersing and capping ability.

Fourier Transform Infrared (FTIR) spectroscopy is a powerful tool for

identifying the types of chemical bonds (functional groups) in a molecule by

producing an infrared absorption spectrum that is like a molecular "fingerprint". The

wavelength of the light absorbed is characteristic of the chemical bond as can be

seen in this annotated spectrum. Figure 2 shows the FTIR spectra of as-prepared

ZnO/MgO samples dried at 120ºC. The peaks observed in the spectra at 3685-2840,

206

1604 and 1390 cm–1 are the stretching and bending vibrations of –OH groups, which

are associated with the adsorbed water on the surface of the ZnO/MgO particles [23].

Fig. 2 FTIR spectra of (a)

ethanol, (b) water-ethanol

and (c) water mediated

ZnO/MgO samples dried at

120°C

The band appeared at 1096 cm−1 was assigned to the C–N stretching vibration

[24]. Generally, the metal oxides give absorption bands below 1000 cm–1, arising

due to the inter-atomic vibrations. Further, the strong bands located at 746 and 530

cm−1 indicate the stretching vibration mode of Mg–O and Zn–O, respectively, which

confirm the formation of ZnO/MgO nanocomposites [25].

Figure 3 (a-c) shows the UV-vis absorption spectrum of the ZnO/MgO

nanocomposites prepared in ethanol, ethanol-water and water, respectively. It can be

seen in all the spectra that the strong absorption peaks were appeared at around 280

nm, which is attributed to the band gap absorption in ZnO/MgO nanocomposites.

The calculated values of the band gap energies of ethanol, ethanol-water and water

mediated ZnO/MgO nanocomposites are 3.83, 3.75 and 3.66 eV respectively, which

are good agreement with reported band gap values of ZnO/MgO nanocomposites

[28]. Moreover, MgO is more ionic compared to ZnO, because of 3s energy level in

Mg and 4s energy level in Zn. Consequently, the energy difference between these s

levels and O 2p level is smaller in ZnO and larger in MgO. Thus, ionicity is lowest

in ZnO and largest in MgO. This is now consistent with larger band gaps for

ZnO/MgO as compared to ZnO [26].

207

Fig.3 UV-vis absorption

spectra of ZnO/MgO

nanocomposites prepared

in(a) ethanol, (b) water-

ethanol and (c) water

According to the data of the absorption spectra, the optical band gap (Eg) of

the ZnO/MgO nanocomposites can be estimated, by using the following equation:

αh = C (h–Eg)n

Here α is the absorption coefficient, h is the photon energy, C is the

constant, and n=1/2 for a directly allowed transition. For the indirect transitions, the

plots of (αh)2 versus photon energy of the ZnO/MgO nanocomposites are shown in

the inset of Fig. 3. Hence, the optical band gap for the absorption peak can be

obtained by extrapolating the linear portion of the (αh)2–h curve.

Optical investigations can reveal very useful information for understanding

the physical properties of materials. They also demonstrate the possibility of

extending the potential application

of ZnO/MgO nanocomposites in

optoelectronic devices. Therefore,

the photoluminescence emission

measurement was performed with an

excitation wavelength of 300 nm.

Fig. 4 PL emission spectra of

ZnO/MgO nanocomposites

prepared in (a) ethanol, (b) water-ethanol and (c) water

208

Figure 4 (a-c) shows the room-temperature PL emission spectra of ethanol,

ethanol-water and water mediated ZnO/MgO nanocomposites. Generally, ZnO/MgO

nanocomposites grown in the chemical solution has two kinds of defects, i.e.,

intrinsic defect and surface defects. The PL emission spectra of all the samples show

the broad and strong deep level emissions (DLE) in the green emission region

centered at ~ 513–548 and 560 nm, respectively, indicating that the prepared

nanocomposites have a good crystal quality [27]. The DLE is associated with the

intrinsic defects in the ZnO/MgO nanocomposites, and is attributed to the radiative

recombination of photo-generated holes with electrons [28]. Moreover, the DLE

bands are mainly attributed to the intrinsic defects, such as oxygen vacancy, zinc

vacancy, magnesium vacancy, oxygen interstitial, zinc interstitial and magnesium

interstitial or surface-related defects [29, 30]. Since, it was observed from the PL

emission spectra that there was a change in the intensity of the emission peaks by the

alcoholic medium mediated samples (Fig.4.a-b)) than that of aqueous medium,

which lead us to conclude that the alcoholic solvents changed the crystalline size or

increased the intrinsic and surface defect [31].

4. Conclusion

Different solvents such as ethanol, ethanol-water and water mediated

ZnO/MgO nanocomposites have been successfully synthesized by the facile

precipitation process. The hexagonal/cubic structure of ZnO/MgO nanocomposites

was confirmed by the powder XRD patterns and the average particle size of the

samples calculated to be 22, 23.91 and 25.82 nm. It was found that the solvents

played important roles in the preparation of size of nanocomposites. The presence of

functional groups of synthesized ZnO/MgO samples was confirmed by the FTIR

spectrum. The optical properties of the nanocomposites were studied by UV-vis and

PL spectroscopies. The band gap energies of ethanol, ethanol-water and water

mediated ZnO/MgO nanocomposites are 3.83, 3.75 and 3.66 eV respectively, which

are good agreement with reported band gap values of ZnO/MgO nanocomposites.

The PL emission studies showed deep level emissions (DLE) in the green emission

region, indicating that the prepared nanocomposites have a good crystal quality.

Moreover, the DLE bands are mainly attributed to the intrinsic defects, such as

oxygen vacancy, zinc vacancy, magnesium vacancy, oxygen interstitial, zinc

209

interstitial and magnesium interstitial or surface-related defects. Hence, it should be

suitable for optoelectronic devices.

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211

ACOUSTICAL STUDIES ON THE EFFECT OF ALKYL ALCOHOL ON

THE MICELLATION OF SURFACTANT IN AQUEOUS SOLUTION

AT FIXED FREQUENCY 2 MHZ AND FIXED

TEMPERATURE OF 303.15K.

G. Lakshiminarayanan1 and D. Arun kumar2

1,2Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai.

ABSTRACT

Ultrasonic velocity, density and viscosity studies have been carried out in

aqueous solutions of sodium oleate and in aqueous solutions of sodium oleate

containing 5-20% V/V of ethanol (ET). These studies are carried out in sodium

oleate concentration of 3mM to 12mM at a fixed frequency of 2MHz and at a fixed

temperature of 303.15K. The variation of ultrasonic velocity in aqueous solutions of

sodium oleate containing 5-20% V/V of ET sodium oleate concentration exhibiting a

break at critical micelle concentration (CMC). The ultrasonic velocity, adiabatic

compressibility, free length, free volume and internal pressure also exhibiting a

break at CMC similar to velocity curve. The results are discussed in terms of

formation of sodium oleate micelles through hydrophobic interaction and hydrogen

bonding.

INTRODUCTION

Molecular interaction in liquid mixtures has been the subject of numerous

investigation in recent past years [1-3].The systems shows a wide verity of physical

properties. Resent researchers have studied the interaction of sodium oleate (SO)

with alcohol through ultrasonic techniques. But the effect of ethanol on SO is

scandy. The aim our present investigation is to determine ultrasonic studies on the

effect of ethanol on the micellization of sodium oleate in aqueous solutions at

fixed frequency of 2 MHz and fixed temperature of 303.15 k. The results are

interpreted in terms of formation of SO micelles in the solutions.

MATERIALS AND METHODS

The sodium oleate (SO) used in the present study are of AR/BDH grade

purchased from SD-fine chemicals Ltd., India and they are used as such without

further purification. The solvents used namely ethanol are of spectroscopic grade.

Triply distilled deionised water is used for preparing the solutions of methanol.

212

Ultrasonic velocity studies are carried out at a fixed frequency of 2 MHz in the

sodium oleate concentration range of 3mM to 12mM. Ultrasonic velocity is

measured using a Digital Ultrasonic Velocity meter (Model VCT-70A, Vi-

Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at 303.15K by

circulating water from a thermostatically controlled water bath and the temperature

being maintained to an accuracy of ±0.1oC. The accuracy in measurement of

velocity and absorption is ±2 parts in 105 and 3% respectively. Shear viscosity and

density of aqueous solutions of SO containing 5-20% V/V of ET are determined

using an Oswald’s viscometer and a graduated dilatometer respectively. The

accuracy in measurement of density and viscosity is ±2 parts in 104 and ± 0.1%

respectively. From the measured values of ultrasonic velocity, density and viscosity,

the various other parameters such as adiabatic compressibility (βs), intermolecular

free length (Lf), free volume (Vf ) and internal pressure (Пi) are calculated using

standard formulae.

COMPUTATIONS OF PARAMETERS

Adiabatic compressibility (βs), intermolecular free length (Lf), free volume

(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),

respectively.

βs = 1/C2ρ (1)

Lf = KT βs 1/2 (2)

Vf = (M C / K η)3/2 (3)

πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)

where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M

is effective molecular weight, K is constant for liquids, b is constant, T is

temperature.

RESULT AND DISCUSSIONS

From the measured values of ultrasonic velocity and viscosity, the other

parameters such as adiabatic compressibility, free length, free volume and internal

pressure were computed and shown in graphically in figures (1-6).The variations of

ultrasonic velocity against concentration of sodium oleate in aqueous solution are

213

given in Fig 1. The measured ultrasonic velocity increases with increasing

concentration of sodium oleate in aqueous solutions and exhibits sharp break at a

particular concentration is known as Critical Micellar Concentration (CMC), which

is confirmed by G.Ravichandran et al [4]. The increase in ultrasonic velocity before

CMC is due to the oleate ions making hydrogen bond with water molecules. The

micelle formation in aqueous solution of sodium oleate and higher aggregation leads

to increase in velocity beyond CMC.

The measured ultrasonic velocity increases with increasing concentration of

sodium oleate in aqueous – alcoholic solvent (5-20%V/V of ethanol) mixtures of

solution and exhibits sharp break at a particular concentration of sodium oleate

(i.e.)., CMC as shown in Fig 1. The increase in ultrasonic velocity is due to the

alcoholic solvents act as a structure breaker in aqueous sodium oleate. Sodium ions

are restricting the mobility of the water molecules. This leads to increase in

ultrasonic velocity before CMC. The micelle formation in aqueous-alcoholic

solution of sodium oleate and higher aggregation leads to increase in velocity after

CMC of solution. In addition to average dipole moment of sodium oleate in the

solution also contributes increase in ultrasonic velocity. The velocity observed in

aqueous-alcoholic solvent at particular compositions (volume by volume) in the

order:

Velocity of 5% ET mixture < Velocity of 10 % ET mixture < Velocity of 15 % ET

mixture < Velocity of 20 % ET mixture

From the figure 1, it is observed that when the 5% V/V of ethanol is added to

the aqueous solution of sodium oleate, the CMC of aqueous solution of sodium

oleate shifted towards the higher concentration side (6.8 mM). This is due to the

lowering of the average dielectric constant of the medium because of the dielectric

constant of water is greater than methanol.

Similarly, when the 10-20% V/V of methanol is added to the aqueous solution

of sodium oleate the CMC of aqueous solution of sodium oleate shifted towards the

higher concentration side in the order of (7.2 mM), (8.4 mM), (8.8 mM),

respectively.

214

0.002 0.004 0.006 0.008 0.010 0.0121560

1565

1570

1575

1580

1585

1590

1595

1600

1605

1610

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

Ultr

ason

ic V

eloc

ity (m

s-1)

Molar Concentration of Sodium Oleate

0.002 0.004 0.006 0.008 0.010 0.012

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

Visc

osity

10-4

NSm

-2

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

0.002 0.004 0.006 0.008 0.010 0.0123.96

3.98

4.00

4.02

4.04

4.06

4.08

4.10

4.12

4.14

4.16

Adi

abat

ic C

ompr

essi

bilit

y( b

s )X1

0-10 N

-1m

2

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

0.002 0.004 0.006 0.008 0.010 0.0124.13

4.14

4.15

4.16

4.17

4.18

4.19

4.20

4.21

4.22

4.23

Free

Len

gth

L f x 1

0-10 m

Molar Concentration of Sodium Oleate

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

Adiabatic compressibility, free length and free volume, internal pressure

studies supports the ultrasonic velocity studies in aqueous and aqueous alcoholic

solvents mixtures.

CONCLUSION

In the present study, the ultrasonic velocity, density, viscosity and internal

pressure increases whereas adiabatic compressibility, free length and free volume

decreases with increasing concentration of sodium oleate in aqueous and aqueous –

alcoholic mixture (Ethanol).

The CMC value obtained in with aqueous with 20 % V/V alcoholic solvent

(Ethanol) mixture is greater than all other compositions of alcohols concentrations of

sodium oleate solutions. This is due to the higher breaking nature of alcohol in

higher compositions.

Figure – 1 Figure - 2

Figure - 3 Figure - 4

215

0.002 0.004 0.006 0.008 0.010 0.0123.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

5.0

5.2

5.4

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

Free

Vol

ume

(Vf)

m3

Molar Concentration of Sodium Oleate0.002 0.004 0.006 0.008 0.010 0.012

2.90

2.95

3.00

3.05

3.10

3.15

3.20

3.25

3.30

3.35

3.40

Water + SO Water + 5 % ET + SO Water + 10 % ET + SO Water + 15 % ET + SO Water + 20 % ET + SO

Inte

rnal

Pre

ssur

e (p

i) pas

cal

Molar Concentration of Sodium Oleate

Figure - 5 Figure – 6

References

1. Bhattarai A, Chatterjee SK, Deo TK, Niraula TP (2011) Effects of

concentration, temperature, and solvent composition on the partial molar

volumes of sodium lauryl sulfate in methanol (1) + water (2) mixed solvent

media. J Chem Eng Data 56:3400–3405

2. Nain AK, et al. Molecular interactions in binary mixtures of formamide with

1 butanol, 2 butanol, 1,3butaneol at different temperatures. Journal of Fluid

Phase Equilibria, 2008; 265(1-2):46-56.

3. Bhoj Bhadur Gurung, Mahendra Nath Roy, Study of densities, viscosities and

ultrasonic speeds of binary mixtures containing 1, 2 diethoxy ethane with

alkane 1-ol at 298.15 K. Journal of Solution Chemistry. 2006; 35:1587-1606.

4. G.Ravichandran, G.rajarajan, T.K. Nambinarayanan, Journal of Molecular

Liquids 267-276, 102 (2003).

216

Synthesis, growth, structure, optical, and photoconducting

properties of an Inorganic new nonlinear optical crystal:

sodium manganese tetra chloride (SMTC)

M. Packiyaraja, D.Sivavishnuc, G.J. Shanmuga Sundarb and

S. M. Ravi Kumarc* aDepartment of Physics, S.K.P. Engineering College, Tiruvannamalai 606 611

3Department of Physics, Arignar Anna Government Arts College, Cheyyar-604 407 cDepartment of Physics, Government Arts College , Tiruvannamalai 606 603

*corresponding author: smravi78@rediffmail.com

Abstract

A new inorganic nonlinear optical single crystal of sodium manganese tetra

chloride (SMTC) has been successfully grown form aqueous solution by the slow

evaporation technique at room temperature. The crystals obtained by the above

technique were subjected to different characterization analysis. Single crystal X-ray

diffraction study reveals that the crystal belongs to orthorhombic system with non-

centrosymmetric space group Pbam. Optical transmission study on SMTC crystal

shows high transmittance in the entire UV–Vis region and the lower cutoff

wavelength is found to be 240 nm. The second harmonic generation (SHG)

efficiency of the crystal was measured by Kurtz’s powder technique infers that the

crystal has nonlinear optical (NLO) efficiency 1.32 times that of KDP.

Photoconductivity study confirms that the title compound possesses a negative

photoconducting nature.

1.0 Introduction

The well known properties of laser radiation are important for a wide variety

of applications. Laser radiation could be converted into one form of frequency to

another through the nonlinear optics, hence the application of nonlinear optics is

increased significantly in various fields in science and technology. Generally,

nonlinear optical (NLO) interaction is made by one or two laser beam incident on a

suitable material in which an output beam of the desired frequency is produced [1-2].

Harmonic generation, sum and difference frequency generation and parametric

oscillation are included in the NLO interaction [3]. A Lower frequency pair of

217

tunable output beam can be produced only by suitable material when it is interact

(NLO) with high input laser beam. Mostly, NLO interaction imposes several

demands on potential NLO materials. The field of nonlinear optics is one of the most

attractive fields of current research because of its vital applications in various areas

like optical switching, optical data storage for developing technologies in

telecommunication and signal processing [4-6]. Since, the first demonstration was

done in the year of 1961, which reveals that nonlinear frequency conversion is highly

materials-limited field [7]. So materials should be optically transparent, quadratic

susceptibility of sufficient magnitude, allow for phase matching interaction and

withstand the laser intensity without damaging. To date, the most important class of

materials used in nonlinear optics is inorganic single crystals.

Inorganic materials, exhibiting second order nonlinear optical properties have

attracted in the recent past due to their ability to process into crystals, wide optical

transparency domain, large nonlinear figure of merit for frequency conversion, fast

optical response time and wide phase matchable angle [8]. These ionic bonded

inorganic crystals, easy to synthesis with high melting point and high degree of

chemical inertness[9]. Highly polarisable, inorganic quality crystal and their efficient

active second order harmonic generation (SHG) have been observed by Franken et al

and co-workers in 1961[7].

Inorganic materials have advantages over organic materials, such as

architectural flexibility for molecular design and morphology, high mechanical

strength and good environmental stability with non toxicity andusability in high

power applications. Molecular hyperpolarizability of inorganic nonlinear optical

crystal are used in optical switching (modulation), frequency conversion (SHG, wave

mixing) and electro-optic applications especially in EO modulation. Historically,

inorganic NLO materials have been chronicled more extensively inorganic oxide

crystal, LiNbO3, KNbO3, KDP and KTP, etc., have been studied for device

application like piezoelectric, ferroelectric and Electro-optics [10]. This material has

also been formed successful usage in commercial frequency doublers, mixers and

paramedic generators to provide coherent laser radiation with high frequency

218

conversion efficiency in the new region of the spectrum, inaccessible by other

nonlinear crystal conventional sources.

The aim of this research work is to survey the processing and properties of

inorganic nonlinear optical crystal sodium manganese tetrachloride (SMTC) with

molecular formula Na2MnCl4 used in NLO frequency conversion.The structure of

Na2MnCl4 was determined by Goodyear et al in the year of 1971[11]. The grown

crystals of SMTC, chlorine ions coordinated octahedrally with Mn ions and form an

infinite chain parallel to c axis and are held with sodium ions. Sodium ions are

surrounded by four chloride ions at the corners of a trigonal prism. Binding of Mn-Cl

and Na-Cl suggests that the structure is mainly ionic in character.Hence, an attempt

hasbeen made on growth of sodium manganese tetra chloride (SMTC) single crystals

by slow evaporation solution growth technique and its physical-chemical properties

have been investigated for the first time.

2.0 Experimental Procedure

2.1. Synthesis

SMTC salt was synthesized by taking analytical reagent (AR) grade

manganese chloride and sodium chloride in stoichiometric ratio 1:2 with double

distilled water as a solvent. The synthesized SMTC salt has been obtained by the

following chemical reaction.

MnCl2+2NaCl Na2MnCl4

Manganese chloride + sodium Chloride Sodium manganese tetra chloride.

The scheme of the molecular structure of SMTC is as shown below.

Scheme 1 Molecular arrangement of SMTC crystal

219

2.2 Crystal Growth

The prepared solutions were stirred vigorously at RT for 4 h. Continuous

stirring with slightly rise in temperature ensures homogeneity and avoids co-

precipitation of motives. Purification of synthesized salt was achieved by successive

recrystallization process. The saturated mixture of solution was filtered two times

with micron pore sizeWattmann filter paper. This synthesized clean solution was

poured into a Petri dish and covered by polythene paper with pores, and allowed for

slow evaporation of the water solvent. After a time span of 35 days, the solvent was

evaporated and good quality SMTC crystal of dimensions 22 1 mm3 were

harvested from the Petri dish. The growth rate was found to be 0.12mm per day. The

grown crystal was defect less, optically transparent and with no inclusions. As-

grown crystal of SMTC is shown in the figure 1.

Fig. 1 Photograph of as grown crystals of SMTC

3.0 Characterization of SMTC Single Crystal

The grown crystal of SMTC was subjected to single crystal and powder XRD

analysis using ENRAF NONIOUS CAD4 X-ray diffraction meter and BRUKER,

Germany (model D8 advance) X-ray diffractometer. Transmission behavior of the

grown crystal was studied by using LAMBDA-35 UV-visible spectrophotometer.

The NLO efficiency of the grown crystal was tested by KURTZ powder technique

using ND:YAG laser of wavelength

1064 nm. Mechanical behaviour of the grown sample was investigated by Vicker’s

220

microhardness tester. Dielectric constant and dielectric loss studies were carried out

by using HIOKI3532 HITESTER LCR meter. Keithley 485 PICOAMMETER was

used to study the photoconductivity of the grown SMTC crystal.

3.1 Results and Discussion

3.1.1 Single crystal XRD studies.

The Single crystal XRD study confirms the unit cell parameters of as grown

SMTC crystals a=6.93 Å, b=11. 82 Å, c=3. 86 Å,= β ==90 and volume of the cell

is found to be, 316.182 Å3. Hence the SMTC crystal is Orthorhombic in structure

and in thespace group Pbam. The lattice parameters are well coincide with a reported

value [11].

3.1.2 Linear optical transmission studies

Since NLO crystals can be for practical use only when it has wide

transparency window. The transmission range of SMTC crystal was determined by

recording the optical transmission spectrum in the wavelength region of 200 - 900

nm. The optical transmission spectrum of SMTC crystal is shown in the figure 2.

Optically polished single crystal of thickness 2mm was used to study the

transmission behavior of SMTC. This recorded spectrum, gives information about

the structure of the molecule by absorption of UV and the visible light involves

promotion of electrons in the and orbital from ground state to a higher energy

state [12]. The transmission spectrum shows that the grown crystal has a lower cutoff

wavelength at 240 nm,which attributes the electronic transmission in the SMTC

crystal. Absence of absorbance in the region between 240 nm and 900 nm is an

essential property of the nonlinear optical crystals. Single crystals are mainly used in

optical applications and hence an optical transmittance window and the transparency

lower cutoff wavelength (200-400) is very important for the realization of the SHG

output in the range for using lasers. Optical width of the as grown crystal SMTC

was compared with NaCl and Mncl2 complex inorganic crystals. The grown SMTC

crystal has good transparency in UV-visible and IR region which ensures, that

crystal can be used as sensor materials from UV, visible in the IR ranges and may be

consider as a potential candidate for the photonic and optoelectronic applications

[13]. The graph has been plotted to estimate the direct band gap values using Tauc’s

221

relation. The Tauc’s plot has been drawn between (αhν)2 and hν as shown in the

figure 3. The band gap value is obtained by extrapolating the straight portion of the

graph to hν axis at (αhν)2=0. The estimated band gap value of grown sample SMTC

is 5.4eV.

Fig. 2 UV-Visible spectrum of SMTC crystal

1 2 3 4 5 6 7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Eg=5.4ev

(alp

ha.h

v)2 .e

v2 .mm

2

hv(ev)

Fig. 3 Tauc’s plot of SMTC crystal

3.1.3 Second harmonic generation efficiency measurement

In order to confirm the nonlinear optical property, powdered sample of

SMTC was subjected to Kurtz and Perry techniques, which remains a powerful tool

for initial screening of materials for SHG [14]. The fundamental beam of wavelength

1064 nm from Q switched mode locked Nd:YAG laser was made to fall normally on

the powder from of grind sample which was made available between two transparent

222

glass slides. Pulse energy 2.9 mJ/pulse and pulse width 8 ns with a repetition rate of

10 Hz were used. The photo multiplier tube (Hamamatsu R2059) was used as a

detector and 90 degree geometry was employed. The SHG signal generated in the

sample was confirmed from emission of bright green (532 nm) radiation from the

sample. The measured amplitude of second harmonic generation for SMTC crystal is

11.32 mJ and 8.8 mJ for KDP (KDP crystal was powdered to the identical size of

SMTC and used as reference materials). It shows a powder SHG efficiency of SMTC

crystal is about 1.3 times of KDP. The SHG efficiency of SMTC crystal is compared

to few popular inorganic NLO crystals which are given in the table 1.

3.1.4 Photoconductivity studies.

The photoconductivity study of SMTC crystal was carried out by connecting

the sample in series with DC power supply and a picoammeter (Keithley 480) at

room temperature. The details of the experimental setup are reported elsewhere [15].

By increasing the applied field from 10 to 150 V/cm and corresponding dark current

without exposure of radiation was recorded. Photo current was recorded by exposing

the crystal with halogen lamp of power 100 W containing iodine vapour for the same

applied field. Dark current and Photo current against an applied field of same range

were recorded in the same graph [Figure 4]. From the graph, it is observed that dark

and photo current of the grown crystal increase linearly with applied field but

photocurrent less than the dark current. This phenomenon is termed as negative

photoconductivity.

Negative photo conductivity of being as grown crystal SMTC, may be due to

decrease in either no number of free change carriers or their lifetime when subjected

to radiation. Negative Photoconductivity of the grown crystal explained, according to

Stockman model, the forbidden gap in the material contains two energy levels in

which one is situated between the Fermi level and the conduction band while another

is located close to the valence band. The second state has a high capture cross section

for electrons and holes. As it captures electrons from the valence band the number of

charge carriers in the conduction band gets reduced and the currentdecreases in the

presence of radiation [16-18].

223

Fig. 4 Field dependent conductivity of SMTC crystal

4.0 Conclusion

A potential inorganic nonlinear optical single crystal of sodium manganese tetra

chloride was prepared at room temperature by slow evaporation of aqueous

solutions. The well defined external appearance with bright, transparent and

colourless crystals is obtained. The unit cell parameters and the space group were

found using single crystal data. The FT-IR spectrum reveals the functional groups of

the grown crystals. The grown crystal shows 99 % transmission with UV cut-off at

240 nm hence suitable for frequency conversion applications. The SHG efficiency of

the SMTC was measured to be higher than that of KDP. The above experimental

results, viz., bulk size, extremely good crystalline perfection, optical transparency,

SHG efficiency and photoconducting nature of the grown crystal may have possible

NLO applications.

Reference

[1] A. H. Reshak, H. Kamarudin, and S. Auluck, Acentric Nonlinear Optical 2,4-

Dihydroxyl Hydrazone Isomorphic Crystals with Large Linear, Nonlinear

Optical Susceptibilities and Hyperpolarizability, J. Phys. Chem. B 2012, 116,

4677−4683.

[2] Ali Hussain Reshak , I. V. Kityk , and S. Auluck, Investigation of the Linear and Nonlinear Optical Susceptibilities of KTiOPO4 Single Crystals: Theory and Experiment, J. Phys. Chem. B 2010, 114, 16705-16712

0 20 40 60 80 100 120 140 1600.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Curr

ent (

nA)

Electric Field (V/cm)

Id(dark current)

Iph(photocurrent)

224

F. Peter, M.Bordui and Martin,Fejer.Annu. Rev. Mater. Sci. 23 (1993) 321-379.

[3] P.N. Prasad, D.J. Williams. Introduction to nonlinear optical effects in organic molecules and polymers, John Wiley & Sons, Inc., New York, USA (1991).

[4] H.O. Marcy, L.F. Warren, M.S. Webb, C.A. Ebbers, S.P. Velsko, G.C. Kennedy, G.C. Catella, Second harmonic generation in zinc tris(thiourea) sulfate, Appl. Opt. 31 (1992) 5051-5060.

[5] X.Q. Wang, D. Xu, D.R. Yuan, Y.P. Tian, W.T. Yu, S.Y. Sun, Z.H. Yang, Q. Fang, M.K. Lu, Y.X. Yan, F.Q. Meng, S.Y. Guo, G.H. Zhang, M.G. Jiang, Synthesis, structure and properties of a new nonlinear optical material: Zinc cadmium tetrathiocyanate, Mater. Res. Bull. 34 (1999) 2003-2011.

[6] P.A. Franken, A.E. Hill, C.W. Peters, G.Weinreich, Generation of optical harmonics, Phys. Rev. Lett. 7 (1961) 118-119.

[7] H. Nalwa, Seizo Miyata.Nonlinear optics of organic molecules and polymers, CRC press, New York (1996).

[8] C.F. Dewey Jr, W.R. Cook Jr, R.T. Hodgson, J.J. Wynne,Frequency doubling in KB5O84H2O and NH4B5O84H2O to 217.3 nm, Appl. Phys. Lett. 26 (1975) 714–716.

[9] D.S. Chemla, J. Zyss, Nonlinear optical properties of organic molecules and crystals. 01-02, Academic Press, Orlando, New York (1987).

[10] J. Goodyear, S.D.A. Ali, G.A. Steigmann, The crystal structure of Na2MnCl4,

ActaCryst. B27 (1971) 1672-1674. [11] R. Sankar, C.M. Raghavan, M. Balaji, R. Mohan Kumar, R. Jayavel,

Synthesis and Growth of Triaquaglycinesulfatozinc(II), [Zn(SO4)(C2H5NO2)(H2O)3], a New Semiorganic Nonlinear Optical Crystal, Cryst. Growth Des. 7 (2007) 348-353.

[12] Y. Le Fur, R. Masse, M.Z. Cherkaoui, J.F. Nicoud, Z. Kristallogr. 856 (1993). [13] S.K. Kurtz, New nonlinear optical materials, IEEE, J. Quantum Electron. 4

(1968) 578–584. [14] F.P. Xavier, A. Regis Indigo, G.J. Goldsmith, Role of metal phthalocyanine in

redox complex conductivity of polyaniline and aniline black, J. PorphyrinsPhthaloeyanines 3 (1999) 679-686.

[15] V.N. Joshi, Photoconductivity, Marcel Dekker, NewYork, (1990). [16] S. Abraham Rajasekar, K. Thamizhrasan, J.G.M. Jesudurai, D. Premanand, P.

Sagayaraj, The role of metallic dopants on the optical and photoconductivity properties of pure and doped potassium pentaborate (KB5)single crystal. Materials Chemistry and Physics. 84(1) (2004)157-161.

[17] Owczarek,K. Sangwal,Effect of impurities on the growth of KDP crystals: On the mechanism of adsorption on 100 faces from tapering data, J. Cryst. Growth. 99 (1990) 827-831.

225

SYNTHESIS, STRUCTURAL, OPTICAL AND MORPHOLOGICAL

PROPERTIES OF (Co, Ag) doped ZINC OXIDE NANOPARTICLES

J.Balavijayalakshmi a*, K.Meenab

aAssistant Professor, Department of Physics, PSGR Krishnammal College for

Women, Coimbatore, Tamilnadu, INDIA. bPG Student, Department of Physics, PSGR Krishnammal College for Women,

Coimbatore, Tamilnadu, INDIA

Abstract

Co-Ag co-doped Zinc oxide nanoparticles are synthesized by chemical co-

precipitation method. Zinc Chloride, Cobaltous chloride, Silver nitrate and sodium

hydroxide is used as raw materials. The synthesized nanoparticles are subjected to

X-ray diffraction technique to calculate the average nano-crystalline size using

Debye – Scherrer formula and are found to be around 25 nm. The optical properties

are characterized by UV-Vis spectral analysis. The FT-IR spectrum of the sample is

recorded and the characteristic absorption bands are observed. The morphological

analysis of the sample is studied using Scanning Electron Microscope (SEM). These

co-doped (Co, Ag) ZnO nanoparticles may be used as antibacterial reagents to treat

diseases caused by bacteria and fungi.

Keywords: Co-precipitation method, nanoparticles, Debye – Scherrer, FT-IR,

SEM.

1. INTRODUCTION

Zinc oxide nanoparticles have attracted great attention in recent years because

of its unique properties and versatile applications in transparent electronics,

ultraviolet (UV) light emitters, piezoelectric devices, chemical sensors and

spintronics [1-4]. ZnO has high chemical stability and low toxicity, which is widely

used as an active ingredient for dermatological applications in creams, lotions and

ointments on an account of its antibacterial properties [5-7]. Doped ZnO shows

maximum effect against pathogenic organisms as compared to ZnO, there by using

nanoparticles as an antimicrobial agent. Many Literatures have reported the

structural, optical and morphological properties of pure ZnO, Co doped ZnO and Ag

doped ZnO by various methods such as hydrothermal, thermal hydrolysis, sol-gel

and chemical precipitation methods [ 8-12]. Among these methods, co-precipitation

226

method is cost-effective with high yield. Hence in the present investigation, an

attempt is made to synthesize Co-Ag co-doped Zinc oxide nanoparticles by chemical

co-precipitation method.

2. MATERIALS AND METHODS

The chemicals Zinc chloride, Silver nitrate, Cobalt chloride, Sodium

hydroxide used in this study is of analytical grade. Cobalt doped silver nanoparticles

are synthesized by taking stoichiometric amounts of 0.05 aqueous solution of silver

nitrate, 0.85M aqueous solution of zinc chloride and 0.10 M aqueous solution of

cobaltous chloride. The solutions are mixed together. The neutralization is carried

out with sodium hydroxide and the pH of the solution is maintained at 9. Then the

solution is washed with de-ionised water until all the impurities are removed and the

sample is annealed at 500C.

The crystal structure of the synthesized samples is analyzed using XRD

Shimadzu 6000. The FT-IR spectra are recorded using Shimadzu IR affinity-1 to

ensure the presence of the metallic compounds. UV-Visible absorption spectra are

recorded using the SHIMADZU UV-Visible absorption Spectrometer. The

morphology and the microstructure of the samples are tested by scanning electron

microscopy (SEM) using a Hitachi S-3000H microscope.

3. RESULTS AND DISCUSSION

3.1 XRD Structural Analysis

Figure 1. XRD spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C

227

X-ray diffraction pattern of (Co,Ag) doped ZnO nanoparticles annealed at

500 C is shown in Figure 1. The diffractograms showed the characteristic

reflections planes corresponding to (100), (002), (101), (102), (110), (103), (112) and

(201) crystal planes. The peaks are well matched with reference to the JCPDS card

no 36-1451, corresponding to hexagonal wurtzite structure of ZnO [13-14]. It is

observed that the inclusion of cobalt and silver with ZnO have not modified its

wurtzite structure. But the characteristic peak of Ag corresponding to (200) plane is

observed. The peaks are sharper and narrower as the samples are annealed at 500C,

indicating the crystalline nature of the sample. The average particle size (D) is

calculated using the Scherrer formula [15]

D = 0.9λ/(β cosθ)

Where D is the crystalline size, λ is the wavelength of the X-ray radiation, θ is the

diffraction angle, β is the full width at half maximum of the diffraction peak at 2θ.

The average crystallite size from X-ray technique is found to be 22-25 nm.

3.2 FT-IR Spectral Analysis

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0 5 0 0

7 5

8 0

8 5

9 0

9 5

1 0 0

1 0 5

Tran

smitt

ance

(%)

W a v e n u m b e r ( c m - 1 )

Figure 2. FT-IR spectrum of Zn0.85Co0.10Ag0.05O annealed at 500 C

The FT-IR spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C in the wave

number range 4000-400 cm-1 is shown in Figure 2. The absorption bands observed

around 3452cm-1 is attributed to O-H stretching vibrations and the band around

2969cm-1 is due to C-H vibrations. The absorption band around 1720 cm-1 are due to

CO vibrations. The absorption band around 1368 cm-1 is due to ZnO [16-17] and the

band around 720cm-1 corresponds due to the presence of silver ions [18-19].

228

3.3 UV Spectral Analysis

200 300 400 500 600 700 8000.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Abs

orba

nce

Wavelength(nm)

Figure 3. UV-Vis spectrum of Zn0.85Co0.10 Ag0.05O annealed at 500 C

UV Visible spectroscopy is used to study the optical properties of Zn0.85Co0.10

Ag0.05O nanoparticles measured at room temperature in the wavelength range of 200

– 800 nm as shown in Figure 3. The absorption band is observed at 380 nm due to

ZnO nanoparticles. Three additional absorption bands are observed at 565nm, 655nm

and 676nm in the spectra of (Co,Ag) doped ZnO nanoparticles. These additional

absorption bands are due to the co-doping of cobalt and silver ions in ZnO. This may

be attributed due to the sp-d exchange interaction between the band electrons and the

localized d electrons of the dopants [20-21].

3.4 SEM Analysis

Figure 4. SEM micrograph of Zn0.85Co0.10 Ag0.05O annealed at 500 C

Figure 4 shows the scanning electron micrograph of Zn0.85Co0.10 Ag0.05O

nanoparticles annealed at 500C. The micrograph shows sphere like bubbles

distributed uniformly and agglomerated together.

229

4. CONCLUSION

(Co,Ag) doped ZnO nanoparticles (Zn0.85Co0.10 Ag0.05O) nanoparticles are

synthesized by chemical co-precipitation method. The synthesized nanoparticles are

subjected to X-ray diffraction technique to calculate the average nano-crystalline size

using Debye – Scherrer formula and are found to be around 22-25 nm. The optical

properties are characterized by UV-Vis spectral analysis and three additional peaks

are observed. The FT-IR spectrum of the sample is recorded and the characteristic

absorption bands are observed. SEM analysis show regular sphere like bubbles.

These co-doped (Co, Ag) ZnO nanoparticles may be used as antibacterial reagents to

treat diseases caused by bacteria and fungi.

5. REFERENCES

1. Ezenwa I.A., Synthesis and optical characterization of zinc oxide thin film,

Research Journal of Chemical Sciences,2(3), 26-30 (2012).

2. Yang H.M., Nie S., Preparation and characterization of Co-doped ZnO

nonmaterial’s, Mater. Chem. Phys., 114, 279-282 (2009).

3. Yang M., Guo Z.X., Qiu K.H., Long J.P., Yin G.F., Guan D.G., Liu S.T.,

Zhou S.J., Synthesis and characterization of Mn-doped ZnO column arrays,

Appl. Surf. Sci., 256, 4201- 4205. (2010).

4. Irimpan L., Nampoori V.P.N., Radhakrishnan., Spectral and nonlinear optical

characteristics of nanocomposites of ZnO- Ag, Chemical Physics Letters.,

455, 265-269 (2008).

5. Jones, N., Ray, B., Ranjit, K.T., Manna, A.C., Antibacterial activity of ZnO

nanoparticle suspensions on a broad spectrum of microorganisms, Fem.

Microbial. Lett.279, 71-76 (2008).

6. Tam, K.H., Djurisic, A.B., C.M.N. Chan, C.M.N., Xi,Y.Y., Tse, C.W., Leung,

Y.H., Chan, W.K., Leung, F.C.C.,Au, D.W.T., Antibacterial activity of ZnO

nanorods prepared by a Hydrothermal method, Thin Solid Films., 516, 6167 -

6174 (2008).

7. Zhang, L., Ding, Y., Povey, M., York, D., ZnO nanofluids a potential

Antibacterial agent, Prog. Nat. Sci., 18, 939-944 (2008).

230

8. Georgekutty, R., Seery, M.K., Pillai, S.C., A Highly Efficient Ag-ZnO

Photocatalyst: Synthesis, Properties, and Mechanism, J. Phys. Chem. C., 112,

13563-13570 (2008).

9. Zheng, Y., Chen, C., Zhan, Y., Lin, X., Zheng, Q., Wei,K., Zhu, J., Photocatalytic Activity of Ag/ZnO Heterostructure Nanocatalyst: Correlation between Structure and Property, J. Phys. Chem.C.112, 10773 -10777 (2008).

10. Ye X-Y., Zhou Y-M., Sun Y-Q., Chen J., Wang Z-Q., Preparation and characterization of Ag/ZnO composites via a simple hydrothermal route, J. Nanopart. Res. 11, 1159-1166 (2009)

11. Nirmala, M., Anukaliani, A., Characterization of undoped and Co doped ZnO nanoparticles synthesized by DC thermal plasma method, Physica B, 406, 911- 915 (2011).

12. Zhang, Y., Shi, E.W., Chen, Z.Z., Magnetic properties of different temperature treated Co- and Ni-doped ZnO hollow nanospheres, Mater. Sci. Semicond. Process, 13, 132-136 (2010).

13. Pal, B., and Giri, P.K., High temperature ferromagnetism and optical properties of Co doped ZnO nanoparticles, J.Appl. Phys. 108, 084322-1 - 084322- 8 (2010)

14. Zeferino, R.S., Flores, M.B. and Pal, U., Photoluminescence and Raman scattering in Ag-doped Research Journal of Material Sciences ZnO nanoparticles, J. Appl. Phys. 109, 014308-1 - 014308-6 (2011).

15. Cullity B.D., Elements of X-ray diffraction, Addison-Wesely., 1959. 16. Ahmed F., Kumar S., Arshi N., Anwar M.S., Koo B.H.,Lee C.G., Doping

effects of Co2+ ions on structural and magnetic properties of ZnO nanoparticles, Microelectronic Engineering 89, 129-132 (2012).

17. Ullah R., Dutta J., Photocatalytic degradation of organic dyes with manganese-doped ZnO nanoparticles, Journal of Hazardous Materials, 156, 194-200 (2008).

18. S. Suwanboon. Structural and optical properties of nanocrystalline ZnO powder from sol-gel method, Sci. Asia 34(1), pp. 31-34, (2008).

19. A. H. Shah, E. Manikandan, M. Basheer Ahmed and V. Ganesan. Enhanced Bioactivity of Ag/ZnO Nanorods-A Comparative Antibacterial Study. J. Nanomed Nanotechol 4(3), pp.2-6, (2013).

20. Ruby Chauhan, Ashavani Kumar and Ram Pal Chaudhary, Synthesis and characterization of silver doped ZnO nanoparticles, Archives of Applied Science Research, 2 (5):378-385 (2010).

21. Xiao Q., Zhang J., Xiao C., Tan X., Photocatalytic decolorization of methylene blue over Zn1-xCoxO under visible irradiation, Materials Science and Engineering: B, 142, 121-125 (2007).

231

Assessment of Heavy metal Pollution in Coastal Sediments of East Coast of

Tamilnadu using Energy dispersive X-ray Fluorescence Spectroscopy (EDXRF)

N. Harikrishnan1, M. Suresh Gandhi2, Durai Ganesh1, A. Chandrasekaran3,

R. Ravisankar1*

1Post Graduate and Research Department of Physics, Government Arts College,

Thiruvannamalai - 606603, Tamilnadu, India 2Department of Geology University of Madras Guindy Campus, Chennai -600025,

Tamilnadu,India 3Department of Physics, SSN college of Engineering, Kalavakkam, Chennai -

603110, Tamilnadu, India

Email: ravisankarphysics@gmail.com; +91-9840807356

Abstract

The heavy metals concentration and its pollution status of sediments from

Periyakalapattu to Parangipettai of East Coast of Tamilnadu, India were investigated

using EDXRF technique. The concentration of heavy metals Mg, Al, Si, K, Ca, Ti,

Fe, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Ba, La and Pb were determined using energy

dispersive X-ray fluorescence (EDXRF) technique. The mean concentration of heavy

metal found in the order of Mn > Ba > V > Cr > Zn > La > Ni > Si > Pb > Co > As >

Cd > Cu > Al > Fe > Ca > Ti > K > Mg. The pollution indices like contamination

factor (CF), contamination degree (Cd) and modified degree of contamination (mCd)

were calculated to assess the contamination status of metals in sediments. The results

of pollution indices shows that Al, Mg, Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba,

La and Pb are low degree of contamination whereas high degree of contamination

for Cd. This work may be serves as baseline work for future.

Key Words: Sediment, EDXRF, Contamination Degree (Cd), Modified Degree of

Contamination (mCd).

232

1.Introduction

Pollution of the natural environment by metals is becoming a potential global

problem. Coastal and estuarine regions are the important sinks for many persistent

pollutants and they accumulate in organisms and bottom sediments (Szefer et al.,

1995). Sediment pollution by heavy metals has been regarded as a critical problem in

marine environment because of their toxicity and bioaccumulation (Chapman et al.,

1998; Islam and Tanaka, 2004; Singh et al., 2005; Todd et al., 2010). Sediment

analysis is vital to assessing qualities of total ecosystem of a water body in addition

to water sample analysis practiced for many years.

Sediment quality has been recognized as an important indicator of water

pollution (Larsen and Jensen 1989) since sediments are the main sink for various

pollutants, including metals discharged into the environment (Williams et al., 1996;

Balls et al., 1997; Dassenakis et al., 1997; Tam and Wong 2000). Multi-elemental

analysis of sediment may reveal the presence of heavy metals and may have toxic

influence on ground water and surface water and also on plants, animals and humans

(Suciu et al., 2008).

In this work, sediments are addressed for monitoring and assessment of metal

pollution from Periyakalapattu to Parangipettai of East Coast of Tamilnadu, India.

The study area chosen for the heavy metals analysis due to variety of industrial

activities (such as metal smelting, pharmaceuticals etc) and agriculture activities

(which include maize, cassava, sugarcane and vegetables farming) takes place and

may enhance the pollution level. These activities may release toxic and potentially

hazards to the environment of the study area. So this research is geared up to assess

the metal pollution and influence of sources from the toxic metals on the sediments

from East Coast of Tamilnadu. The main objective of this work is (1) to determine

concentrations of metals present in sediments from Periyakalapattu to Parangipettai

of East Coast of Tamilnadu using EDXRF technique (2) to identify the level of

heavy metal contamination status using pollution indices (3) to find out the sources

of heavy metals influenced by of natural and/or anthropogenic (4) to report the

findings.

233

2. Materials and Methods

2.1. Sampling and sample preparation

Sediment samples were collected along the Bay of Bengal coastline, from

Periyakalapattu to Parangipettai coast of Tamilnadu. These samples were collected

in pre-monsoon season, where sediment texture and ecological conditions can be

clearly observed, when erosional activities are predominant, and sediments were not

transported from the river and estuary towards the beach and marine. In order to

ensure minimum disturbance of the upper layer, samples were collected by a

Peterson grab sampler from seabed. The grab sampler collects sediment from the

seabed along the 15 stations (Fig.1).

Table 1. Geographical latitude and longitude for the sampling locations

S.

No

Name of the

Location

Location

ID Latitude Longitude

1 Periyakalapet PKP 12° 1' 46.6320'' N 79° 51' 49.0032'' E

2 Ellaipillaichavady EPC 11° 55' 54.0228'' N 79° 48' 19.1268'' E

3 Auroville ARV 11°59'2.8422"N 79°50'55.5334"E

4 Nadukuppam NDK 11°58'1.7401"N 79°38'35.5103"E

5 Muthialpet MTP 11° 57' 18.2556'' N 79° 50' 4.1712'' E

6 Veerampattinam VMP 11° 54' 5.6160'' N 79° 49' 36.7428'' E

7 Nallavadu NVD 11° 51' 27.6014'' N 79°34'27.46"E

8 Narambai NRB 11° 49' 3.2520'' N 79° 48' 0.9216'' E

9 Thazhankuda TZK 11°46'14.2020"N 79°47'40.5605"E

10 Cuddalore OT COT 11° 45' 0.0000'' N 79° 45' 0.0000'' E

11 Raasapettai RSP 11° 40' 56.2692'' N 79° 46' 17.5008'' E

12 Sitheripettai STP 10° 30' 31.6944'' N 77° 13' 17.7600'' E

13 Betlodai BLD 11° 21' 45.2300'' N 79° 32' 21.8544'' E

14 Samiyarpettai SYP 11° 32' 57.2100'' N 79° 45' 31.8744'' E

15 Parangaipettai PGP 11° 30' 0.0000'' N 79° 46' 0.0012'' E

234

Table 1 represents the geographical latitude and longitude for the sampling

locations at the study area. The sampling locations were selected based on the

prevailing stresses and included areas near the urban and domestic effluent discharge

point. Uniform quantity of sediment samples were collected from all the sampling

stations located between an average interval of 3NM (Nautical mile) and the sample

was kept in a thick plastic bag. Care was taken to ensure that the collected sediments

were not in contact with the metallic dredge of the sampler, and the top sediment

layer was scooped with an acid washed plastic spatula. Sediment samples were

stored in plastic bags and kept in refrigeration at -4ºC until analysis. Then pebbles,

leaves and other foreign particles were removed. The samples were sub sampled

using the coning and quartering method. The sub samples were air dried and larger

stone fragments (>20mm largest diameter) or shells were removed. The samples

were air dried at 105ºC for 24 h to a constant weight and were not separated <63 µm

in order to identify the geochemical concentrations in the whole bulk fraction as the

study area is dominated by sandy layers in many places. Then samples were ground

into a fine powder for 10-15 min, using an agate mortar. All powder samples were

stored in desiccators until they were analyzed.

2.2. EDXRF technique

The prepared pellets were analyzed using the EDXRF available at

Environmental and Safety Division, Indira Gandhi Centre for Atomic Research

(IGCAR), Kalpakkam, Tamilnadu. The instrument used for this study consists of an

EDXRF spectrometer of model EX-6600SDD supplied by Xenemetrix, Israel. The

spectrometer is fitted with a side window X-ray tube (370W) that has Rhodium as

anode. The power specifications of the tube are 3-60kV; 10-5833µA.

Selection of filters, tube voltage, sample position and current are fully

customizable. The detector SDD 25mm2 has an energy resolution of 136eV ± 5eV at

5.9keV Mn X-ray and 10-sample turret enables keeping and analyzing 10 samples at

a time. The quantitative analysis is carried out by the In-built software nEXT. A

standard soil (NIST SRM 2709a) was used as reference material for standardizing

the instrument. This soil standard obtained from a follow field in the central

235

California San Joaquin valley. The soil standard (reference material) (NIST SRM

2709a) analysis value are given in Table 2.

Table-2 Analysis of soil standard-NIST SRM 2709a by EDXRF (mg kg-1)

Element Certified Values EDXRF values

Mg 14600 14900 ± 1000

Al 72100 68400 ± 2300

K 20500 19100 ± 700

Ca 19100 16500 ± 500

Ti 3400 3100 ± 100

Fe 33600 33900 ±1200

V 110 98.8 ± 6.59

Cr 130 112.1 ± 4.01

Mn 529 568.2 ± 19.85

Co 12.8 12.8 ± 0.55

Ni 83 69.3 ± 2.98

Zn 107 127.9 ± 4.88

3.0. Results and discussion

3.1. Metal contents in surface sediments

The concentration of elements in sediments from Periyakalapattu to

Parangipettai along the East Coast of Tamilnadu, southeastern, India is presented in

Table 3. The concentration varies from 25 to 6007 mg kg-1 for Mg; from 13532-

37425 mg kg-1 for Al; from 129139-226500 mg kg-1; from 4468-9350 mg kg-1 for K;

from 4592-21679 mg kg-1 for Ca; from 530-51434 mg kg-1 for Ti; from 3647-57902

mg kg-1 for Fe; from 23.4-711 mg kg-1 for V; from 12.5-207.3 mg kg-1 for Cr; from

68.1-1387.6 mg kg-1 for Mn; from 1.1-19 mg kg-1 for Co; from 15.2-33.63 mg kg-1

for Ni; from BDL-3.60 mg kg-1 for Cu; from 14-89 mg kg-1 for Zn; from 4-7.4 mg

kg-1 for As; from BDL-10.2 mg kg-1 for Cd; from 152.3-416.8 mg kg-1 for Ba; from

BDL-216.7 mg kg-1 for La and from BDL-35.7 mg kg-1 for Pb. The enhancement of

heavy metal (Cr, Mn, Co, Ni, Cu, Zn, As and Cd) concentration in the study area

may be due to many fisher man and tourist activities along the east coast of

236

Tamilnadu in the sediment. Among the heavy metals determined, Aluminum (Al) is

the most abundant metal in the sediments. The mean of metal concentration

decreased in the following order, Si > Al > Fe > Ca > Ti > K > Mg > Mn > Ba > V >

Cr > Zn > La > Ni > Pb > Co > As > Cd > Cu in the study area (Chandrasekaran et

al., 2015).

The locations of Auroville (ARV), Nadukuppam (NDK), Veerampattinam

(VMP), Nallavadu (NVD), Narambai (NRB) is characterized by higher

concentrations of Al, Ti, Fe, V, Cr, Mn, Co & Zn when compared with other

locations. This may be due to the high tourists’ boat activities and other

anthropogenic activities like shipping and harbor activities, industrial and urban

wastage discharges, dredging, etc., (Ravisankar et al., 2015).

From the analysis, the elevated heavy metal levels in the sediments resulted

partially from the anthropogenic activities such as wastewaters, aquaculture activities

and shipping. Table 4 shows the comparison of heavy metal (mg kg-1) concentration

of present work with other countries.

3.2. Contaminant factor (Cf)

Contaminant factor (Cf) is the ratio obtained by dividing the concentration of

each metal in the sediment by the background value (Håkanson, 1980). Cf is

considered to be an effective tool in monitoring the pollution over a period of time

and is given by the formula,

‘‘Cbackground’’ refers to the concentration of metal indicates the concentration

of metal (of interest) in the sediments when there was no anthropogenic input.

According to Håkanson (1980): Cf<1 indicates low contamination; 1<Cf<3 is

moderate contamination; 3<Cf<6 is considerable contamination; and Cf > 6 is very

high contamination.

237

Fig 1. Location map of the study area

238

Table 3. Heavy metal concentration (mg kg-1) of sediment samples of east coast of Tamilnadu, India

S.

No Element Mg Al Si K Ca Ti Fe V Cr Mn Co Ni Cu Zn As Cd Ba La Pb

1 PKP 2223 20696 223285 6615 8943 2039 9534 50.11 42.38 192.26 3.38 20.86 BDL 30.54 4.7 5.5 312.4 12.9 4.4

2 EPC 25 20255 216248 6202 7239 2340 8458 50.9 30.3 180.1 2.8 19.8 BDL 23.0 4.7 2.1 306.1 29.1 1.5

3 ARV 1800 37425 226500 5484 8070 51434 57902 711.0 207.3 1387.6 19.0 24.4 BDL 89.0 6.9 BDL 180.2 216.7 35.7

4 NDK 300 13532 210618 6800 4592 530 3647 23.4 12.5 68.1 1.1 15.2 BDL 14.0 4.0 BDL 411.9 BDL BDL

5 MTP 1028 19066 189935 7869 7406 1216 5520 26.37 21.21 110.05 1.88 16.48 BDL 20.16 4.8 10.2 385.4 BDL 1.4

6 VMP 6007 30893 161332 5044 20809 15464 35269 234.71 127.00 750.16 12.51 33.63 BDL 62.31 6.5 3.4 209.0 47.0 17.0

7 NVD 3022 26895 133697 4468 21176 11689 33771 204.56 123.33 748.38 11.95 33.30 BDL 65.67 5.8 BDL 152.3 31.0 19.8

8 NRB 5051 31132 150205 4850 21679 19539 40489 310.87 155.77 869.09 14.35 30.23 3.60 65.94 7.4 BDL 176.0 51.2 25.5

9 TZK 816 21212 147446 6085 12057 3357 13407 64.94 54.52 243.11 5.01 23.21 BDL 30.78 5.2 1.4 256.7 19.1 9.1

10 COT 1608 19866 129139 5392 11628 3776 13137 71.38 55.33 263.74 4.61 24.59 BDL 29.00 4.7 3.6 236.1 6.4 6.1

11 RSP 795 23554 178547 7286 11363 931 8308 31.85 43.85 157.81 3.10 22.84 BDL 22.47 4.8 2.3 308.2 0.0 6.8

12 STP 1773 22928 202630 9350 11586 724 6693 28.12 30.32 128.35 2.40 21.67 BDL 36.02 5.6 1.8 416.8 1.0 7.6

13 BLD 2072 20975 179547 7147 9403 1583 9530 40.01 66.16 185.61 3.42 23.16 BDL 25.08 4.9 3.8 302.5 3.1 5.5

14 SYP 3440 21775 136994 4859 13169 3469 19281 86.6 112.3 112.3 6.5 32.1 BDL 37.8 4.4 5.1 250.4 18.0 5.0

15 PGP 4612 25167 134370 5232 12027 8814 24594 151.9 118.1 118.1 8.3 30.4 BDL 45.0 5.0 2.8 224.0 6.0 9.4

Average 2305 23691 174699 6179 12076 8460 19302 139.11 80.03 367.65 6.68 24.80 3.60 39.79 5.3 3.8 275.2 36.8 11.1

239

Table 4. Comparison of heavy metal (mgkg-1) concentration of present work

with other countries

S

No

.

Location Cr Mn Co Ni Zn References

1 Tinto River,

Spain 11-151 -

6.8-

42 1.6-36

68-

5280

Morillo et al.,

(2002)

2 Bremen Bay,

Germany 131 - - 60 790

Hamer and

Karius, (2002)

3 Danube River,

Europa

26.5-

556.5

442-

1655 -

17.5-

173.3

78-

2010

Woitke et al.,

(2003)

4 Pearl River

estuary 89 - - 41.7 150 Zhou et al., (2004)

5 Masan Bay,

Korea 67.1 - - 28.8 206.3

Hyun et al.,

(2007)

6 Kafrain Dam,

Jordan 160 730 60 100 120

Ghrefat et al.,

(2011)

7

East Coast of

Tamilnadu,

India

115.18 427.5 6.96 32.48 43.63 Ravisankar et al

(2015)

8

Periyakalapat

tu to

Parangipettai

coast,

Tamilnadu,

India

80.03 367.65 6.68 24.80 39.79 Present Study

240

The Contaminant Factor in sediments from Periyakalapattu to Parangipettai,

along the East Coast of Tamilnadu, southeastern India is presented in Table 5. The

results of Cf'’s are 0.002 to 0.400 (average 0.154) for Mg, 0.15 to 0.43 (average

0.27) for Al, 0.17 to 0.35 (average 0.23) for K, 0.29 to 1.35 (average 0.75) for Ca,

0.12 to 11.18 (average 1.84) for Ti, 0.08 to 1.23 (average 0.41) for Fe, 0.18 to 5.47

(average 1.07) for V, 0.14 to 2.30 (average 0.89) for Cr, 0.08 to 1.63 (average 0.43)

for Mn, 0.06 to 1.00 (average 0.35) for Co, 0.31 to 0.67 (average 0.50) for Ni, 0.15

to 0.94 (average 0.42) for Zn, 0.00 to 0.08 (average 0.01) for Cu, 0.31 to 0.57

(average 0.41) for As, 0.00 to 34.07 (average 9.35) for Cd, 0.26 to 0.71 (average

0.47) for Ba, 0.00 to 2.36 (average 0.32) for La and 0.00 to 1.78 (average 0.52)

respectively with the order of Cd > Ti > V > Cr > Ca > Si > Pb > Ni > Ba > Mn > Zn

> Fe > As > Co > La > Al > K > Mg > Cu.

The Cf values of the elements Co, Ni, Cu, & As indicates low contamination

where as moderate contamination noticed for the elements Cr & Cd. The high

contamination was observed in most of the locations (Muthialpet (MTP – 34.07);

Periyakalapet (PKP – 18.19); Samiyarpettai (SYP – 16.91); Betlodai (BLD – 12.77);

Cuddalore OT (COT – 12.14); Veerampattinam (VMP – 11.26); Parangaipettai (PGP

– 9.41); Raasapettai (RSP – 7.80) and Ellaipillaichavady (EPC – 7.00) for Cd. The

location Auroville (ARV) registered high values for the elements Cr, Co & Zn in Cf .

The Cf value of the elements Ni & As noticed high value in the locations of

Veerampattinam (VMP – 0.67) and Narambai (NRB – 0.57) respectively. The

enrichment of heavy metals may originate from non-point sources such as

agricultural pollution (e.g, fertilizers and livestock manure), atmospheric transport

and other industrial activities). The heavy metals accumulation can be attributed to

other sources such as municipal waste waters, mine discharge, irrigation discharge,

and local rivers and creeks, along with erosion of rocks and parent soil materials

(Dai et al., 2007; Cheng and Hu, 2010; Hosono et al., 2011). Fig 4 shows the

variation in CF values of heavy metals with locations.

241

Fig 4. Variation of CF values of heavy metals in locations

3.3. Contamination degree (Cd)

To facilitate pollution control, Hakanson (1980) proposed a sediment logical

approach using a diagnostic tool named the ‘degree of contamination’. Cd was

determined as the sum of the Cf for each sample:

----------------- (2)

For contamination degree, Hakanson (1980) proposed this classification: Cd<6

indicates a low degree of contamination; 6<Cd<12 is a moderate degree of

contamination; 12<Cd<24 is a considerable degree of contamination; and Cd > 24 is

a high degree of contamination, indicating serious anthropogenic pollution. The

calculated Contamination degree value of 0.47 for Al; 0.40 for Mg; 0.35 for K; 1.35

for Ca; 11.18 for Ti; 1.23 for Fe; 5.47 for V; 2.30 for Cr; 1.63 for Mn; 1.00 for Co;

0.67 for Ni; 0.94 for Zn; 0.08 for Cu; 0.07 for As; 34.07 for Cd; 0.72 for Ba; 2.36 for

La and 1.78 for Pb .The obtained Contamination degree value for the elements Al,

Mg,Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba, La & pb shows the low degree of

contamination. Ti shows the moderate degree of contamination whereas Cd

exhibited high degree of contamination from its value of 34.07. This may be due to

recent increase in major industrial (in the coastal areas) and a minor harbor activity

that involves movement of naval vessels throughout the year may increase the

contamination levels in coastal areas. Table 5 shows the contamination degree (Cd)

of sediment samples of east coast of Tamilnadu, India. Fig 5 shows the variation of

Cd values of heavy metals in locations.

242

Table 5. Contamination factor (Cf), Contamination Degree (Cd) and Modified Degree of Contamination (mCd) of sediment

samples of east coast of Tamilnadu, India

Element S.

No Location

ID

Si Al Mg K Ca Ti Fe V Cr Mn Co Ni Zn Cu As Cd Ba La Pb

1 PKP 0.81 0.24 0.148 0.25 0.56 0.44 0.20 0.39 0.47 0.23 0.18 0.42 0.32 - 0.36 18.19 0.54 0.14 0.22

2 EPC 0.79 0.23 0.002 0.23 0.45 0.51 0.18 0.39 0.34 0.21 0.15 0.40 0.24 - 0.36 7.00 0.53 0.32 0.08

3 ARV 0.82 0.43 0.120 0.21 0.50 11.18 1.23 5.47 2.30 1.63 1.00 0.49 0.94 - 0.53 - 0.31 2.36 1.78

4 NDK 0.77 0.15 0.020 0.26 0.29 0.12 0.08 0.18 0.14 0.08 0.06 0.31 0.15 - 0.31 0.00 0.71 - -

5 MTP 0.69 0.22 0.069 0.30 0.46 0.26 0.12 0.20 0.24 0.13 0.10 0.33 0.21 - 0.37 34.07 0.66 - 0.07

6 VMP 0.59 0.35 0.400 0.19 1.30 3.36 0.75 1.81 1.41 0.88 0.66 0.67 0.66 - 0.50 11.26 0.36 0.51 0.85

7 NVD 0.49 0.31 0.201 0.17 1.32 2.54 0.72 1.57 1.37 0.88 0.63 0.67 0.69 - 0.44 - 0.26 0.34 0.99

8 NRB 0.55 0.35 0.337 0.18 1.35 4.25 0.86 2.39 1.73 1.02 0.76 0.61 0.69 0.08 0.57 - 0.30 0.56 1.27

9 TZK 0.54 0.24 0.054 0.23 0.75 0.73 0.28 0.50 0.61 0.29 0.26 0.46 0.32 - 0.40 4.78 0.44 0.21 0.45

10 COT 0.47 0.23 0.107 0.20 0.73 0.82 0.28 0.55 0.61 0.31 0.24 0.49 0.31 - 0.36 12.14 0.41 0.07 0.30

11 RSP 0.65 0.27 0.053 0.27 0.71 0.20 0.18 0.24 0.49 0.19 0.16 0.46 0.24 - 0.37 7.80 0.53 - 0.34

12 STP 0.74 0.26 0.118 0.35 0.72 0.16 0.14 0.22 0.34 0.15 0.13 0.43 0.38 - 0.43 5.94 0.72 0.01 0.38

13 BLD 0.65 0.24 0.138 0.27 0.59 0.34 0.20 0.31 0.74 0.22 0.18 0.46 0.26 - 0.37 12.77 0.52 0.03 0.28

14 SYP 0.50 0.25 0.229 0.18 0.82 0.75 0.41 0.67 1.25 0.13 0.34 0.64 0.40 - 0.34 16.91 0.43 0.20 0.25

243

15 PGP 0.49 0.29 0.307 0.20 0.75 1.92 0.52 1.17 1.31 0.14 0.44 0.61 0.47 - 0.38 9.41 0.39 0.07 0.47

Average 0.64 0.27 0.15 0.23 0.75 1.84 0.41 1.07 0.89 0.43 0.35 0.50 0.42 0.01 0.41 9.35 0.47 0.32 0.52

Contamination

Degree (Cd) 0.47 0.40 0.35 1.35 11.18 1.23 5.47 2.30 1.63 1.00 0.67 0.94 0.08 0.07 34.07 0.72 2.36 1.78

Modified Degree of

Contamination

(mCd)

0.22 0.13 0.19 0.63 1.53 0.34 0.89 0.74 0.366 0.29 0.41 0.35 0.004 0.34 7.79 0.40 0.27 0.43

- N.D – Not determined

Fig 5. Shows the variation in Cd and mCd values of heavy metals in locations

244

3.4. Modified degree of contamination (mCd)

The modified degree of contamination was introduced to estimate the overall

degree of contamination at a given site according to the formula (Abrahim and

Parker, 2008):

----------- (3)

For the classification and description of the modified degree of contamination

(mCd) in sediments, the following gradations are proposed: mCd<1.5 is nil to a very

low degree of contamination; 1.5 < mCd<2 is a low degree of contamination; 2<

mCd <4 is a moderate degree of contamination; 4< mCd<8 is a high degree of

contamination; 8< mCd <16 is a very high degree of contamination; 16< mCd <32 is

an extremely high degree of contamination; mCd >32 is an ultra-high degree of

contamination.

The calculated modified degree of contamination value 0.22 for Al; 0.13 for

Mg; 0.19 for K; 0.63for Ca; 1.53 for Ti; 0.34 for Fe; 0.89 for V; 0.74 for Cr; 0.36 for

Mn; 0.29 for Co; 0.41 for Ni; 0.35 for Zn; 0.004 for Cu; 0.34 for As; 7.79 for Cd;

0.40 for Ba; 0.27 for La and 0.43 for Pb. From obtained values of modified degree of

contamination of Al, Mg, K, Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu, As, Ba, La & Pb

registered very low degree of contamination. Ti noticed low degree of contamination

from its value of 1.53 whereas Cd showed high degree of contamination of its value

7.79. Table 5 shows the modified degree of contamination (mCd) of sediment

samples of east coast of Tamilnadu, India. Fig 5 shows the variation of mCd values

of heavy metals in locations.

4.0. Conclusion

Distribution of Mg, Al, Si, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd,

Ba, La, and Pb in sediment samples were determined along the east coast of

Tamilnadu using EDXRF technique.

The mean concentration of studied elements followed as Al > Fe > Ca > Ti >

K > Mg > Mn > Ba > V > Cr > Zn > La > Ni > Pb > Co > As > Cd > Cu.

245

The obtained mean concentration values are compared with different

countries.

The results of pollution indices Al, Mg ,Ca, Fe, V, Cr, Mn, Co, Ni, Zn, Cu,

As, Ba, La Pb shows low degree of contamination from contamination degree

(Cd) and modified degree of contamination (mCd).

The heavy metals Cd noticed high contamination from the contamination

degree (Cd) and modified degree of contamination (mCd) values. This may be

due to anthropogenic activities in the study area.

This work may be more extensive studies in this filed for future plans.

Acknowledgement

We are sincerely thanks and gratitude to Dr. K. K. Satpathy, Head,

Environment and Safety Division, RSEG, EIRSG, Indira Gandhi Centre for Atomic

Research (IGCAR), Kalpakkam- 603 102 for giving permission to make use of

EDXRF facility in RSEG and also our deep gratitude and thanks to Dr. M. V. R.

Prasad, Head, EnSD, RSEG, IGCAR, Kalpakkam- 603102, India for his keen help

and constant encouragements in EDXRF measurements. Our sincere thanks to Mr.

K. V. Kanagasabapathy, Scientific Officer, RSEG, IGCAR for his technical help in

EDXRF analysis.

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248

SYNTHESIS, GROWTH AND PHYSICOCHEMIC AL PROPERITIES OF

DIAMMONIUM TETRACHLORO ZINCATE NLO CRYSTALS (DTCZ)

*S.M.Ravikumar and 1G.Nathiya

*Asst. professor, PG& Research Department of physics, Govt. Arts college

Tiruvannamalai-606 603

1Asst. professor, PG& Research Department of physics, Shanmuga Industries Arts and

ScienceCollege, Tiruvannamalai-606 601

ABSTRACT

Diammonium tetrachlro zincate was synthesized by taking diammonium chloride

and zinc chloride in 2:1. New crystals of ATCZ were grown by slow evaporation of an

aqueous solution at room temperature. The grown crystals were characterized by

powder X-ray diffraction (PXRD) analysis, FTIR studies, UV-visible studies. Dielectric

studies and photoconductivity studies and NLO activity of the grown crystal have been

checked by second harmonic generation (SHG) test. The grown crystals have been

subjected to powder X-ray diffraction to identify the crystalline nature. FTIR analyses

was done to confirm the present of various functional group in (DTCZ) crystalline using

Nd-YAG laser the NLO property of the crystal is studied. The transmittance and

absorption of the crystal was studied by UV-Visible spectrometer. Dielectric constant

and dielectric loss were identified by using HIOKI model 3532-50 LCR HITESTER.

The photo conducting nature of the grown crystal was studied by pico ammeter (

Keithly 485 ).

KEY WORDS: Solution growth, FTIR, XRD, SHD, Optical material.

INTRODUCTION:

Non-linear optics is a very useful technology because it extends the usefulness of

lasers by increasing the number of wavelength available both longer and

Shorter than the original can be produced by non-linear optics.

A versatile and highly efficient non-linear optical frequency conversion material

is of vital importance for many applications in the field of photonics and

249

optoelectronics. The interest of the researchers on NLO crystal is not confined just to

their NLO properties. Among these materials show large non-linear linearity, low

angular sensitivity and good mechanical hardness.

NLO crystals has emerged as one of the most attractive field of current research

in view of its vital applications in areas like optical modulation, optical switching,

optical logic frequency shifting and optical data storage for the developing technologies

in telecommunication and inefficient signal processing[1-5].

The search for new, very efficient non-linear materials, for fast and optimum

processing of optical signals has become very important, because of development of

optical fiber communication, laser based imaging and remote sensing etc. In many of

the organic NLO materials there is a solid framework of conjugated electronics along

with weak Vander Waals and hydrogen bonds which are responsible for their NLO

properties.

4 techniques at room temperature. The grown crystals were subjected to various

characterization studies like structure analyze by single and powder diffraction and the

presence of functional groups in the sample was investigated by Fourier transform

infrared spectrometer. The linear and non-linear optical property were carried by UV-

VIS absorption spectrometer and Kurtz and Perry Powder technique. The dielectric

behavior was analyzed. The photo conducting nature of the crystal has been carried out.

EXPERIMENTAL PROCEDURE:

SYNTHSIS OF ATCZ:

Required amount of the commercially available ammonium chloride and Zinc

chloride taken in the molar ratio (2:1) were dissolved in double distilled water to

synthesis diammonium tetra chlro salt. All the starting materials were of analytical

reagent (AR) grade. The synthesis salt was obtained by the following chemical reaction.

2(NH4Cl) + Zncl2 – (NH4)2 cl4Zn

2( Ammonium chloride ) + Zinc chloride –Diammonium tetra chloride Zincate

250

The solution was stirred for about 3 hours using a magnetic stirrer to yield a

homogenous mixture.

Growth of ATCZ crystal

The saturated of diammonium tetra chloro zincates was prepared double distilled

water. The solution was filtered and poured into the Petri was covered by transparent

sheet with few holes were made on it. The solution was kept in undisturbed condition.

The solution was allowed to evaporate slowly. After 10 to 15 days, good transparent

seed crystals were harvested. In the period 30 -35 days, the crystal with dimension

25x8x4 mm3 was obtained. The growth crystal has no inclusion, free from impurities,

defect free with good transparent nature. As grown crystal of ATCZ is shown in the

figure 1.0

Fig: 1.0 photograph of as grown crystal of ATCZ

CHARACTERISATION METHODS:

Single crystal XRD is rescored using Enraf CAD-4 diffractometer with MOKα

(λ=0.1770Ao) radiation. Powdered XRD spectrum of the crystal is recorded using

Rigaku X-ray diffractometer with CuKα radiation. FTIR spectra of Diammonium

tetrachlro zincate was record using a beuker IFS66 FTIR spectrophotometer at room

temperature in the range 400-4000cm-1 by KBr pellet method. The optical absorption

spectrum of ATCZ was studied in the wavelength range 190-900nm by a Varian carry

5E model spectrophotometer. To confirm the non-linear optical property Kurtz and

Perry powder SHg test was carried out for the grown crystal using Nd:YAG Q-

251

switched laser emitting the first harmonic output of 1064nm. The temperature

dependent dielectric constant and dielectric loss was carried out by using a HIOKI

3532-LCR Hit ester. The photo conducting nature of the grown sample was investigated

by PICO Ammeter ( keithley 485 ).

Single crystal X-ray diffraction:

Single crystal X-ray diffraction analysis was carried out using an Enraf CAD-4

diffractometer with MOKα (λ=0.1770Ao) radiatuion. From this analysis it was

observed that the grown crystal of ATCZ belongs to orthorhombic crystal system

having non- centrosymmetry space group with Pmc21.Lattice parameters have been

determined as:a =12.6197,b=7.2107 and c=9.2746 Ao;α=β=ϒ=90 which are in good

agreement with the reported values[6].

Powder X-ray diffraction:

Powder X-ray diffraction data were collected for the grown single crystals. The

pattern was recorded using a Raiku X-ray diffractometer with MOKα (λ=0.1770Ao)

radiation. The powdered sample was scanned in the range 10-90oc at a scan rate of

2/min. In the powder XRD pattern well

defined peaks are observed which reveals

that the grown crystal ATCZ has highly

crystalline nature. The various planes of

ATCZ crystal has been indexed in the

powder XRD pattern. The observed

PXRD pattern of ATCZ is shown in the

fig 1.1

Fig 1.1: powder x-ray diffraction spectrum

252

Fourier Transform Infrared (FTIR) spectroscopy studies:

The infrared spectral analysis is effectively used to understand the chemical

bonding and it provides information about molecular structure of the synthesized

compound. Crushed powder of diammonium tetra chloro zincate crystal was pelletized

using KBr. The spectrum was recorded using a thermo Nicollet v-200 FTIR

spectrometer in the range 400-4000 cm-1 wave number region. The FTIR spectrum of

ATCZ is shown in fig.1.2

The peak around 3196, 2378 cm-1 is due to N-H stretching vibration. The peak at

2988.2795 cm-1 is O-H stretching. The peak of IR spectrum at 2378, 2203 cm-1 is due to

stretching of C≡C. The peak around 1887, 1844 cm-1 is due to C=O stretching vibration.

A peak at 1651 cm-1 has been assigned to C=C stretching vibration. The peak obtained

at 1553 cm-1 for N=O stretching vibration. A

peak 1381 cm-1 is due to C-H deformation. C-C

stretching curve obtained at 997 cm-1. Stretching

of C-Cl are assigned at 676,603 cm-1 stretching

vibration of C-Br are assigned at 577 cm-1. The

band assignment of FTIR spectrum of

Diammonium tetra chloro zincate (ATCZ).

Crystal details shown in table 1.0

Fig 1.3: FTIR spectrum of ATCZ crystal

Table 1.0: Bands assignments of FTIR spectra of ATCZ

Wave number(cm-1) Assignments

3196,2378 N-H Stretching

2988,2795 O-H Stretching

2378,2203 N-H Stretching

1887,1884 N=O Stretching

253

1651 N-H deformation

1553 N=O Stretching

1381 N=O asymmertric

577 NH3+ Torsional oscillation

Optical absorption study:

The grown crystals of pure ATCZ were cut and polished into plates of suitable

dimension to carry out the optical transmission studies. A spectrum was recorded in the

region 190-900 nm using VARIAN CARY 5E model spectrophotometer. The UV-VIS

NIR transmission spectrum of ATCZ crystal is shown in the Fig 1.2.In the UV visible

and IR region, the material found to be transparent. This transparent nature extends the

application of ATCZ in photonics. It is well known that an efficient NLO crystal has an

optical transparency loe cut-off wavelength between 200 and 400nm. The crystal shows

good transmittance in the visible region and the lower cut-off wavelength is 22onm.

Fig 1.2 UV-VIS-NIR spectra of ATCZ single crystal

NLO test:

The SHG property of the grown crystal was tested by the Kurtz and Perry

powder method [7].The powdered sample of ATCZ crystal was illuminated using the

fundamental beam of 1064nm from Q-Switched ND:YAG laser. A photomultiplier tube

(Hamamatsu R2059) was used as the detector and the 90 degree geometry was

employed. The light emitted from the sample was detected by a detector and measured

254

using an oscilloscope. Second harmonic radiation generated by the randomly oriented

micro crystals was focused by a lens and detected by a detector. The optical signal

generated from the sample was converted into an electrical signal and was measured an

oscilloscope. The output of ATCZ is 8.6mJ and it is compared to standard value of

potassium dihydrogen phosphate (KDP) is 8.8mJ. Hence it was found that SHG

efficiency of growth crystal is almost equivalent to KDP.

Dielectric study:

Figure 1.3 and 1.4 show the variations of dielectric constant and dielectric loss

with log frequency for as grown crystal of ATCZ. The dielectric constant of the sample

was measured for different frequencies under various temperature slots from 308 K and

368 K. It is observed from the plot (fig 1.3) that the dielectric constant constant

exponentionally with increasing frequency and then attains almost a constant value in

the high frequency region starting from 3KHz to 6MHz. The similar trend is also

observed form figure 5.6 that the dielectric loss is decreases with increasing frequency

and attains constant after the frequency of 2.5MHz. It is observed that at all

temperatures, both the dielectric constant and dielectric loss decrease with increasing

frequency.

At lower frequency, the dielectric constant is high due to blocking of charge

carrier at electrodes. With increasing temperature, a high degree of dispersion in the

permittivity occur at lower frequency due to space charge effect.

The characteristics of low dielectric

constant and dielectric loss with high frequency

for a given sample suggests that the sample

possesses enhanced optical quality with lesser

defects and this parameter is of vital importance

for various nonlinear optical materials and their

applications[8].

Fig.1.3 Variation of dielectric constant with log frequency for ATCZ

255

Fig1.4 Variation of dielectric loss with log frequency for ATCZ

Photoconductivity study:

Photoconductivity study of the ATCZ single crystal was carried out by using

keithly 485 picoammeter. By not allowing any radiation to fall on the sample and by

varying applied field from 100 to 3000 V/cm, the corresponding dark current values

shown by the picoammeter were recorded. To measure the photo current, the sample

was illuminated with a halogen lamp (100W) containing iodine vapor by focusing a spot

of light on the sample with help of a convex lens. The applied field was increased from

100 to 3000 V/cm and the corresponding photo current was record. The photo current

and dark current are plotted as a function of the applied field (Fig 1.5). It is observed

from the plot that the dark current is always higher than the photo current, hence it is

concluded that ATCZ exhibits negative photoconductivity. The stockman model also

explains the phenomenon of negative photo conductivity successfully.

Fig 1.5 Field dependent photoconductivity of ATCZ single crystal

256

CONCLUSION:

Single crystal of ATCZ was grown by slow evaporation technique. The single

crystal XRD reveals that crystal belongs to orthorhombic crystal system with non

centrosymmetry space group pmc21. The crystalline nature and various planes are

identified by powder XRD. The various functional groups presented in ATCZ was

conferred by FTIR studies. The UV cut-off wavelength was determined in 210nm,

which is main property for NLO application.SHG studies reveals that ATCZ equals to

known NLO material KDP. The variation of dielectric constant at dielectric loss was

analyzed. The grown crystal exhibited negative photo conductivity nature.

REFERENCES:

1. Nalwa H S & Miyata S,Non-linear optics of organic Molecules and polymers

(CRC press,Newyork)1997.

2. Prasad P N & Willams DJ, Introduction to Non-linear optical effects in Organic

molecules and polymersb(Wiley, Newyork),1991.

3. Hann R A & Bloor D (Eds), Organic materials for Non-linear optics, (The Royal

society of chemistry),1989.

4. Badan J,Hiere R,Perigand A, et al (Ed), Non-linear optical properities of organic

molecules and polymeric materials, American chemicals symposium series 233,

(American society Washington, DC),1993.

5. Chemla D S & Zyss J (Eds), Non-linear optical properties of organic molecules

and crystals (American press, Newyork),1987

6. P.Angeli mary, S.Dhanuskodi, Cryst. Res. Technol 36,1231 (2001).

7. S.K.Kurtz, T,T.perry, J. Appl. Phys. 39,3798 (1968).

8. Balrew C and Duhlew R (1984), Application of the hard and soft acids and bases

concept to explain legend in double salt structures, J. Solid state Chemistry, Vol.

55.pp. 16.

257

VARIATIONAL ITERATION METHOD FOR BURGER EQUATION

M.Sudhalakshmi1, R.Sivakumar2 1Department of Physics, Shanmuga Industries Arts and Science College,

Tiruvannamalai District- 606601, Tamil Nadu 2Department of Physics, Pondicherry University, Pondicherry - 605 014

ABSTRACT.

The Variational iteration method (VIM) attracted much attention in the past few

years as a promising method for solving non linear differential equations. Unlike

numerical methods which provide only first or second order accurate results and

require high performance Computing facilities with a few teraflops of computing

power, variational iteration method not require any linearization procedures to solve

the PDEs under consideration and also no computing facilities are needed. Burger

equation is a well known and simple nonlinear equation in the study of fluid and

aerodynamics simulation. Hence, we applied this technique to solve the Burger

equation. The results show that this method gives reasonably accurate values

compared with analytical solution even with two iterations itself and hence it is

considered as a powerful alternative to numerical techniques where possible. It is

also observed that extending this method to solve other nonlinear PDEs, though

appears straightforward, is not easy because we have to start with an initial solution

that may be close to actual solution, which in general is not possible for practical

problems.

Key words: Variational iteration method; Burgers equation.

1. INTRODUCTION

Modern mathematics and symbol computation has posed a challenge of handling

strongly nonlinear equations which cannot be successfully dealt with by classical

methods. It is very easy to find the solutions of linear systems by means of computer.

But, it is still very difficult to solve nonlinear problems either numerically or

theoretically. The fact is various discredited methods or numerical simulations apply

iteration techniques to find their numerical solutions of nonlinear problems, all of

them are sensitive to initial solutions and difficult to obtain converged results in

strong nonlinearity. Variational iteration method (VIM) [14] is uniquely qualified to

258

address this challenge, the flexibility and adaptation provided have made the method

a strong candidate for approximate analytical solution and wide applications in

various fields. It provide physical insight into the nature of the solution of the

problem and find accurate solution among all the possible trial-functions. The

convergence VIM is systematically discussed by Tatari and Dehghan. J.H.He first

applied the variational iteration method to fractional differential equations revealing

a great success. Abbasbandy applied the variational iteration method to Riemann-

Liouville's fractional derivatives, draganescu and his colleagues to nonlinear

vibration with fractional derivative successfully applied. He applied this method to

autonomous ordinary differential systems and nonlinear equations with convolution

product nonlinearity, Abulwafa et al. to nonlinear coagulation problem with mass

loss and to nonlinear fluid flows in pipe-like domain, Ariel et al. to axisymmetrical

flow over a stretching sheet. Problems arising in Adomian Decomposition Method

can be completely eliminated by Variational Iteration Method.

2. HE'S VARIATIONAL ITERATION METHOD

He [6]-[17] has recently attracted a great deal of attention for solving easily and

efficiently a number of nonlinear functional equations. The main feature of the

proposed Variational Iteration Method [9, 29] is the solution of a mathematical

problem with linearization assumption is used as initial approximation (trial-

function), and then a more highly precise approximation at some special point can be

obtained. VIM by including all direction variables [20] called the global variation

iteration method (GVIM). By a variational approach, He's method turns the

functional equation into a recurrence sequence of functions is the exact solution. The

keystone of the VIM is a generalized Lagrange multiplier determined by stationary

conditions imposed on an appropriate correction functional.

xgxTu (1)

where T is a differential operator acts on sufficiently smooth functions u defined on

some interval. The function g is given, and defined for all x . The VIM is based on

splitting T into linear and nonlinear operators as follows:

z)y,x,g(t, Nu (u)L (u)L (u)L (u)L zyxt (2)

259

where zyxt L andL ,L,L are linear operators of z y, x,t, respectively. N is a nonlinear

operator, and z) y, x,g(t, is a known analytical function or the source inhomogeneous

function. Numerical solutions using n th approximations show the high degree of

accuracy and in most cases nu and nv the n th approximation is accurate for quite

low of )3( nn .

2.1. Correction Function. Variational iteration method [8], constructs the

correction functional as, where general Lagrange multipliers can be identified via

variational theory. The non linear term and the analytical function usually taken as

correction.

,0,0

~

1

ndssgsuNsLustutu

t

nnnn (3)

2.2. Restricted Variation. In 3 He [8]-[18] took the variations in nonlinear term,

the analytical function and sometimes the linear term are variation as restricted so as

to find the approximate Lagrange multiplier which helps in solving the equation to

get the exact solution. The variation operator on the restricted variation term leads to

zero i.e. 0~

nu . The subscript denotes n the n th-order approximation.

2.3. Stationary Condition. The extrem point of a surface ),,( yxzz where the first

differential, ),,(1 yxzz vanishes called stationary point or the extremum point of

the surface.

2.4. Lagrange Multiplier. One can enforce the constraints by applying the Lagrange

multiplier rule. Lagrange multipliers [25, 21, 20] known well in optimization and

calculus of variation, identified optimally via integration by parts. The successive

approximations 0,,1 ntxun of the solution txun ,1 will be readily obtained upon

using the Lagrangian multiplier obtained and by using any selective function 0u . The

initial values 0,xu and 0,xut are usually used for the selective zeroth

approximation 0u . Having determined, then several approximations

,0,, jtxu j can be determined. Consequently, the solution is given by nn uu lim .

Lagrange multiplier is nothing else but the retarded Green function for some

differential operators, making easier the study of the convergence of iteration

formulas.

260

3. BURGER EQUATION

Burger's equation [2, 27] is a useful model equation which governs shock wave,

acoustic transmission, traffic and aerofoil flow theory, turbulence and supersonic

flow as well as a prerequisite to the Navier-Stokes equations. It is a useful model

equation applied to complicated fluid flow problems and interesting challenge for the

control design. Numerical methods such as finite difference or characteristics

method need a large amount of computation and the effect of round-off error which

causes the loss of accuracy. Analytical methods for solving Burger's equation are

very restricted and can be used in very special cases; so they cannot be used to solve

equations of numerous realistic scenarios. He's variational iteration method is a

powerful device for solving functional equations.

3.1 ONE DIMENSIONAL BURGER EQUATION

2

2 ,,,,x

txux

txutxut

txu

(4)

with the initial condition and boundary condition

)sin()0,( xxu in , (5)

,0),1(),0( tutu 0t (6)

where , is the interval (0,1).

By VIM, correction function as,

(7)

Applying the variational operator on both sides we get

Applying He's calculus of variation

(8)

dxuxttxtxut

nttn 0

'nn1 ,)(/,u/)(,u),(

261

dxuxtt

ntt 0

'n ,)(/,u/)(1

we get the stationary conditions as,

(9)

(10)

The Lagrange multiplier can be identified as,

1)(1/ tt (11)

Substituting 11 in 7 we get,

(12)

We start with an arbitrary initial approximation that satisfies 5

(13)

Using 13 and Substituting 0n in 12

dx

xx

xxxxtxut

0

2

2

1)sin()sin()sin(sin)sin(),(

=

txtxxxtxu 21 sincossinsin, (14)

Using 13 and Substituting 1n in 12

txtxxxtxu 22 sincossinsin,

262

dtxxxxt

2

0

sincossinsin

t

xxxx0

2sincossinsin

dxxxxx

2sincossinsin

dxxxxx

t2

02

2

sincossinsin

(15)

txu ,2 txtxxx 2sincossinsin txtxx 2sincossin

dxxxxtxtxxxt

0

322222 )cos()(cossincos*sincossinsin

dxxxxx

t

0

32222 )cos()(cossincos

Using a basic trigonometric identity,

xxxx 2222 cos1sin1cossin

txu ,2 txtxxx 2sin21cossinsin

232222 cos21cossin

23 txxintxx

33333 cossin32cossin

31 txxtxx

txxtxx 32342 cossin21cossin

txtxxtx 235234 sincossin31sin

31

24223 sin21cossin2 txtxx (16)

263

We now calculate the numerical results of the solution of one dimensional Burger

equation 4 using the equation 17. The value is compared with the analytical solutions

obtained from the infinite series of Cole (1951) for 1 and 05.0 .

10

1

cosexp

sinexp2,

22

22

n

tnn

n

tnn

xnnaa

xnnatxu

(17)

Where dxxa 1

0

10 cos12exp

and 1,cos1exp2exp2 11

0

ndxxan

The error in the solution obtained by Variational Iteration Method is the absolute

difference between the analytical values and 16. The solutions are tabulated in the

tables 1, 2, 3, 4. From these tables we observe the absolute error is smaller than 710

even for second iteration. To reduce the error further, we continue with higher

iterations. In the case of ,01.0 17 is not available due to slow convergence of the

infinite series.

Table 1: Numerical results for ),(2 txu obtained by VIM method in comparison with the

analytical solution when 1 at 001.0t

x

Analytical solution VIM solution Absolute error

0.1 0.30509 0.305088779442865 -1.2206e-006

0.2 0.58057 0.580565715583992 -4.2844e-006

0.3 0.79962 0.799622134163804 2.1342e-006

0.4 0.94082 0.940816977865164 -3.0221e-006

0.5 0.99018 0.990174197811924 -5.8022e-006

0.6 0.94261 0.942608939642337 -1.0604e-006

0.7 0.80252 0.802521594140596& 1.5941e-006

0.8 0.58347 0.583465181635796 -4.8184e-006

0.9 0.30688 0.306880751049611 7.5105e-007

Table 2: Numerical results for ),(2 txu obtained by VIM method in comparison with the

264

analytical solution when 1 at 01.0t

x

Analytical solution VIM solution Absolute error

0.1 0.27324 0.273735811016050 4.9581e-004

0.2 0.52156 0.522331167664062 7.7117e-004

0.3 0.72185 0.722561260871781 7.1126e-004

0.4 0.85459 0.854983558978212 3.9356e-004

0.5 0.90571 0.905713400017763 3.4000e-006

0.6 0.86833 0.868036910800391 -2.9309e-004

0.7 0.74410 0.743686942574091 -4.1306e-004

0.8 0. 54282 0.543462924377093 -3.5708e-004

0.9 0.28700 0.286798992412058 -2.0101e-004

Table 3: Numerical results for ),(2 txu obtained by VIM method in comparison with the

analytical solution when 1 at 001.0t

x

Analytical solution VIM solution Absolute error

0.1 0.30795 0.307944996153760 -4.7762e-006

0.2 0.58601 0.586005982917996 -3.6487e-006

0.3 0.80713 0.807125933170980 -3.6985e-006

0.4 0.94966 0.949661807529539 2.0352e-006

0.5 0.99950 0.999501708362594 1.7084e-006

0.6 0.95151 0.951506106166328 -4.1215e-006

0.7 0.81011 0.810110075965496 -2.9240e-007

0.8 0.58899 0.588990131787523 -2.3658e-007

0.9 0.30979 0.309789304620123 -9.2304e-007

Table 2: Numerical results for ),(2 txu obtained by VIM method in comparison with the

analytical solution when 05.0 at 01.0t

x VIM solution Absolute error

265

Analytical solution

0.1 0.29865 0.298657507832716 7.5078e-006

0.2 0.57044 0.570450730987659 1.0731e-005

0.3 0.79034 0.790332422257759 -7.5777e-006

0.4 0.93696 0.936947206244648 -1.2794e-005

0.5 0.99460 0.994585517200631 -1.4483e-005

0.6 0.95513 0.955134884175102 4.8842e-006

0.7 0.81976 0.819765618112585 5.6181e-006

0.8 0.59988 0.599890001853205 1.0002e-005

0.9 0.31686 0.316855015336998 -4.9847e-006

4. CONCLUSION

. In this work, we have reviewed available literature, of numerical and analytical

methods on solving PDE's. We have selected one of the available analytical method

called Variational Iteration Method. We have applied VIM to solve various forms of

Burger equation. From the solutions we find that even with a very few iterations one

can get reasonably accurate solutions as we seen in the Tables 1 to 4. This indicates

that VIM is a powerful technique to find analytical solutions of PDE's.

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[27] J.A. Atwell, J.T. Borggaard, B.B. KING, Reduced Order Controllers for

Burgers Equation with a Nonlinear Observer. Int. J. Appl. Math. Comput. Sci. 11

(2001) 13301311 .

[28] S.M. Goh , M.S.M. Noorani , I. Hashim, A new application of variational

iteration method for the chaotic Rossler system. Chaos, Solitons and Fractals 42

(2009) 16101604 .

[29] A.M. Kawala, Numerical solution for Ito coupled systems. Acta Appl. Math.106

(2009) 335325 .

[31] A. Ghorbani , J.S. Nadjafi, An effective modification of He's variational

iteration method. Nonlinear Analysis: Real World Applications. 10 (2009)

28332828 .

[32] B.D.Hahn, Essential Matlab for Scientists. Elsevier 2002.

[33] J. Zhang, G. Yan, Lattice Boltzmann method for one and two-dimensional

Burgers equation. Physica A 387 (2008), 47864771 .

268

GROWTH AND CHARACTERIZATION OF L-ALANINE MIXED

BISTHIOUREA CADMIUM BROMIDE(LABTCB) CRYSTAL

*A. Maniselvan and 1T.Kubendiran

*Asst. professor, PG& Research Department of physics, Shanmuga Industries Arts and Science College, Tiruvannamalai-606 601

1Asst. professor, PG& Research Department of physics, Govt. Arts college

Tiruvannamalai-606 603

ABSTRACT

L-alanine mixed bisthioureacadmium bromide (LABTCB) single crystal has

been grown by slow evaporation method.The grown crystal has been characterized

by single crystal XRD analysis, powder XRDanalysis, FTIR analysis, UV-Vis-NIR

analysis and SHG studies. XRD analysis confirms thecrystalline nature of the

materials. The presence of various functional groups present in LABTCB crystal has

been confirmed by FTIR analysis. The UV-Vis-NIRspectrum shows the transmission

characteristics of the crystals. The SHG study depicts thenonlinear optical efficiency

of the crystal.

KEY WORDS: Solution growth, FTIR, XRD, SHD..,

INTRODUCTION:

Non-linear optics is a very useful technology because it extends the

usefulness of lasers by increasing the number of wavelength available both longer

and Shorter than the original can be produced by non-linear optics.

A versatile and highly efficient non-linear optical frequency conversion

material is of vital importance for many applications in the field of photonics and

optoelectronics. The interest of the researchers on NLO crystal is not confined just to

their NLO properties. Among these materials show large non-linear linearity, low

angular sensitivity and good mechanical hardness.

NLO crystals has emerged as one of the most attractive field of current

research in view of its vital applications in areas like optical modulation, optical

269

switching, optical logic frequency shifting and optical data storage for the

developing technologies in telecommunication and inefficient signal processing[1-5].

The search for new, very efficient non-linear materials, for fast and optimum

processing of optical signals has become very important, because of development of

optical fiber communication, laser based imaging and remote sensing etc. In many of

the organic NLO materials there is a solid framework of conjugated electronics

along with weak Vander Waals and hydrogen bonds which are responsible for their

NLO properties.

4 techniques at room temperature. The grown crystals were subjected to various

characterization studies like structure analyze by single and powder diffraction and

the presence of functional groups in the sample was investigated by Fourier

transform infrared spectrometer. The linear and non-linear optical property were

carried by UV-VIS absorption spectrometer and Kurtz and Perry Powder technique.

The dielectric behavior was analyzed. The photo conducting nature of the crystal has

been carried out.

Growth by Slow evaporation method

LABTCB crystal is synthesized by dissolving AR grade thiourea and AR

grade cadmium bromide in the molar ratio 2:1 in distilled water. The saturated

solution of cadmium bromide was slowly added to the saturated solution of

thiourea.Then was added drop by drop . This was stirred well to get a clear solution.

Pure BTCB crystal was synthesized according to the reaction:

2[CS (NH2)2] + CdBr2 → Cd [CS (NH2)2]2 Br2

The solution was purified by repeated filtration. The saturated solution was

kept in a beaker covered with polythene paper. For slow evaporation 6 or 7 holes

were made in the polythene paper. Then the solution was left undisturbed in a

constant temperature bath (CTB) kept at a temperature of 35 °C with an accuracy of

± 0.1° C. As a result of slow evaporation, after 75 days colorless and transparent

pure BTCB crystals were obtained.

270

Single Crystal X-ray diffraction analysis of L-Alanine mixed BTCB crystals

The single crystal XRD analysis of L-Alanine mixed BTCB crystal was

carried out using ENRAF NONIUS CAD 4 single crystal X-ray diffractometer with

Mokα (λ=0.071073Å) radiation. From the XRD data, it was observed that the L-

Alanine mixed BTCB crystal belongs to tetragonal crystal system and its lattice

parameters are found to be a=9.234Å b=13.747Å c=13.75Å.

Powder X-ray diffraction analysis of L-Alanine mixed BTCB crystals

The grown crystal of L-Alanine mixed BTCB crystals were crushed into fine

powder and powder X-ray diffraction analysis have been carried out using Rich

Seifert X-ray diffractometer.

Figure: Powder XRD pattern of LABTCB crystal

The sample was subjected to intense X-ray of wavelength 1.5406 Å (CuKα) at

a scan speed of 1° per minute to obtain lattice parameters. The recorded patternwas

shown in Figure. The observed diffraction pattern has been indexed by Reitveld

index software package. The lattice parameters have been calculated by Reitveld unit

cell software package. It is found that there is a close agreement with values obtained

by single crystal. The lattice parameters are found to be, a=9.2143Å, b=13.7394Å

and c=13.7533Å.

271

FTIR spectrum analysisof L-Alanine mixed BTCB crystals

The FTIR spectroscopy studies were used to analyze the presence of

functional groups in synthesized compound. The FTIR spectra LABTCB was

recorded using Perkin Elmer spectrometer model spectrum RX1 using KBr pellet

technique in the range 4000 - 400 cm-1 and shown in Fig. The characteristic

vibrational frequencies of the functional groups of L alanine mixed BTCB have been

compared with thiourea. The comparison of characteristic vibrational frequencies has

been tabulated in Table: 1

Figure: FTIR spectrum of LABTCB crystal.

NH stretching vibration of thiourea was observed at 3376 cm-1. The same vibration

wasobserved at 3395 cm-1 in LABTCB crystal. An NCN symmetric bending

vibration was observed in pure thiourea at 494 cm-1 and the same vibration was

observed in LABTCBat 471 cm-1. C=S asymmetric stretching vibration wasobserved

in pure thiourea near 1417 cm-1, the same vibration was also observed in LABTCB

at 1392 cm-1.

272

Table: 1 Vibrational assignments of thiourea and LABTCB crystals

In the FTIR spectra, the NH stretching vibrational bands of NH2 asymmetric

stretching were

observed around 3280

cm-1, 3281 cm-1 and

3285 cm-1. The NH2

symmetric stretching

vibrations are observed

around 3167 cm-1, 3194

cm-1 and 3197 cm-1.

These bands were

shifted to higher wave

number region when compared to that of the free ligand. This shift may be due to the

S.No BTCB

(cm-1)

LABTCB

(cm-1) ASSIGNMENT

1 3376 3395 NH Stretching

2 3280 3285 NH2 asymmetric stretching

3 3167 3197 NH2 asymmetric stretching

4 1627 1619 NH bending

5 1472 1490 CN asymmetric stretching

6 1417 1392 CS asymmetric stretching

7 1089 1089 CN symmetric stretching

8 740 709 CS symmetric stretching

9 494 471 N-C=N symmetric bending

273

increase in the polar character of thiourea molecule because of the formation of

S→M bonds in L-alanine mixed BTCB complex. The band observed around

1627 cm-1 corresponds to NH bending vibration of thiourea. The same vibration was

observed at 1619 cm-1 in LABTCB. The bands observed around 1490 cm-1 were

identified as the C-N asymmetric stretching vibration.The bands observed around

709 cm-1 corresponds to C=S stretching vibration. The bands for CN symmetric

stretching vibration in the grown crystal were observed around 1089 cm-1. The

standard IR bands of thiourea and LABTCB are compared along with their

assignments and are presented in Table1. It is found that the CN stretching (1089 and

1472 cm-1) bands of thiourea are shifted to higher frequencies for LABTCB.Also the

CS stretching bands of thiourea (1417 and 740 cm-1) are shifted to lower frequencies

in LABTCB. These results reveal that the metals coordinate with thiourea through

sulphur. The slight variation in the observed frequencies of LABTCB is due to the

presence of L-alanine.

V-VIS spectral analysis of LABTCB crystal

Figure shows UV-Vis-NIR spectrum of LABTCB crystal

The absorption and transmission spectrum of LABTCB was recordedusing

UV-Vis-NIR spectrophotometer in the range from 190nm to 1100nm using Cary 500

scan UV-Vis-NIR spectrometer and it is shown in Fig. The crystal shows a good

transmittance in the visible region which enables it to be a good material for

optoelectronic applications. As observed in the spectrum, LABTCB was transparent

in the region from 259 nm to 1100 nm. The lower cut off wavelength for LABTCB

is found at 259 nm. The wide range of transparency suggests that the crystals are

good candidates for nonlinear optical applications. The shift of lower

cutoffwavelength in UV region is due to mixing of L-alanine and is desirable for

optoelectronic application.

274

Second Harmonic GenerationEfficiency measurement

The second harmonic generation test was carried out by classical powder

method developed by Kurtz and Perry. It is an important and popular tool to evaluate

the conversion efficiency of NLO materials. The fundamental beam of 1064 nm

from Q switched Nd: YAG laser was used to test the second harmonic generation

(SHG) property of LABTCB crystal. Pulse energy 2.9 mJ/pulse and pulse width 8 ns

with a repetition rate of 10 Hz were used. The photo multiplier tube (Hamamatsu

R2059) was used as a detector and 90 degree geometry was employed. The input

laser beam was passed through an IR detector and then directed on the

microcrystalline powdered sample packed in a capillary tube. TheSHG signal

generated in the sample was confirmed from emission of green radiation from the

sample. The nonlinear optical (NLO) efficiency of LABTCB is 87 mV. The green

light output was detected by a photomultiplier tube. KDP and urea crystals were

powdered to the identical size and were used as reference materials in the SHG

measurement. The SHG relative efficiency of LABTCB crystal was found to be

7.9times higher than that of KDP and 0.836 times that of urea Table 3.

Table: 2 Comparative study of NLO efficiency

Crystal NLO efficiency

(in mV)

LABTCB 87

KDP 11

Urea 104

275

CONCLUSION

The potential semiorganic NLO crystal LABTCB was grown by slow

evaporation method. The grown crystals were characterized by single crystal XRD

analysis, powder XRD analysis, FTIR analysis, UV-Vis-NIR analysis and SHG

studies. The XRD analysis confirms the crystalline nature of the materials. The

presence of various functional groups present in LABTCB crystal has been

confirmed by FTIR analysis. The UV-Vis-NIR spectrum of grown crystal shows that

the crystal is transparent in the wavelength region from 269nm to 1100nm. The SHG

efficiency of the grown LABTCB crystal was 7.9 times greater than the KDP

crystals. Owing to all these properties LABTCB could be a promising material for

NLO applications.

REFERENCES:

1. Nalwa H S & Miyata S,Non-linear optics of organic Molecules and polymers

(CRC press,Newyork)1997.

2. Prasad P N & Willams DJ, Introduction to Non-linear optical effects in

Organic molecules and polymersb(Wiley, Newyork),1991.

3. Hann R A & Bloor D (Eds), Organic materials for Non-linear optics, (The

Royal society of chemistry),1989.

4. Badan J,Hiere R,Perigand A, et al (Ed), Non-linear optical properities of

organic molecules and polymeric materials, American chemicals symposium

series 233, (American society Washington, DC),1993.

5. Chemla D S & Zyss J (Eds), Non-linear optical properties of organic

molecules and crystals (American press, Newyork),1987

6. P.Angeli mary, S.Dhanuskodi, Cryst. Res. Technol 36,1231 (2001).

7. S.K.Kurtz, T,T.perry, J. Appl. Phys. 39,3798 (1968).

276

ULTRASONIC STUDIES ON THE EFFECT OF DMSO AND DMF ON

THE MICELLIZATION OF LITHIUM DODECYL SULPHATE

IN AQUEOUS SOLUTIONS

G. Lakshiminarayanan1 and R. Kumaresan2

1,2Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai. ABSTRACT

Ultrasonic velocity, density and viscosity studies have been carried out in

aqueous solutions of lithium dodecyl sulphate (LDS) and in aqueous solutions of

LDS containing 5-20% V/V of dimethyl sulphaoxide (DMSO), dimethyl formamide

(DMF). These studies are carried out in LDS concentration of 5mM to 14mM at a

fixed frequency of 2MHz and at a fixed temperature of 303.15K. The variation of

ultrasonic velocity in aqueous solutions of LDS containing 5-20% V/V of DMSO

and DMF with LDS concentration exhibiting a break at critical micelle concentration

(CMC). The ultrasonic velocity, adiabatic compressibility, free length, free volume

and internal pressure also exhibiting a break at CMC similar to velocity curve. The

results are discussed in terms of formation of LDS micelles through hydrophobic

interaction and hydrogen bonding.

INTRODUCTION

Molecular interaction in liquid mixtures has been the subject of numerous

investigation in recent past years [1-6]. The system shows a wide verity of physical

properties. Resent researchers have studied the interaction of lithium dodecyl

sulphate (LDS) with aqueous solutions in ultrasonic techniques [7]. But the effect of

aprotic solvent on LDS is scandy. The aim our present investigation is to determine

ultrasonic studies on the effect of DMSO and DMF on the micellization of

lithium dodecyl sulphate in aqueous solutions at fixed frequency of 2 MHz and

fixed temperature of 303.15 k. The results are interpreted in terms of formation of

LDS micelles in the solutions.

MATERIALS AND METHODS

The lithium dodecyl sulphate (LDS) used in the present study are of

AR/BDH grade purchased from SD-fine chemicals Ltd., India and they are used as

such without further purification. The solvents used namely DMO and DMF are of

spectroscopic grade. Triply distilled deionised water is used for preparing the

277

solutions of LDS. Ultrasonic velocity studies are carried out at a fixed frequency of 2

MHz in the lithium dodecyl sulphate concentration range of 5mM to 14mM.

Ultrasonic velocity is measured using a Digital Ultrasonic Velocity meter (Model

VCT-70A, Vi-Microsystems Pvt. Ltd., Chennai, India) at a fixed temperature at

303.15K by circulating water from a thermostatically controlled water bath and the

temperature being maintained to an accuracy of ±0.1oC. The accuracy in

measurement of velocity and absorption is ±2 parts in 105 and 3% respectively.

Shear viscosity and density of aqueous solutions of lithium dodecyl sulphate

containing 5-20% V/V of DMSO and DMF are determined using an Oswald’s

viscometer and a graduated dilatometer respectively. The accuracy in measurement

of density and viscosity is ±2 parts in 104 and ± 0.1% respectively. From the

measured values of ultrasonic velocity, density and viscosity, the various other

parameters such as adiabatic compressibility (βs), intermolecular free length (Lf),

free volume (Vf ) and internal pressure (Пi) are calculated using standard formulae.

COMPUTATIONS OF PARAMETERS

Adiabatic compressibility (βs), intermolecular free length (Lf), free volume

(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),

respectively.

βs = 1/C2ρ (1)

Lf = KT βs 1/2 (2)

Vf = (M C / K η)3/2 (3)

πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)

where, c is ucltrasonic velocity, ρ is density, KT is temperature dependant constant,

M is effective molecular weight, K is constant for liquids, b is constant, T is

temperature.

RESULT AND DISCUSSIONS

From the measured values of density, ultrasonic velocity and viscosity,

the other parameters such as adiabatic compressibility, free length, free volume and

internal pressure were computed and shown in graphically in figures (1-12).The

variations of ultrasonic velocity against concentration of lithium dodecyl sulphate

278

(LDS) in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic

velocity increases with increasing concentration of lithium dodecyl sulphate in

aqueous solutions and exhibits sharp break at a particular concentration is known as

Critical Micellar Concentration (CMC), which is confirmed by Chanchal das et al

[7]. The increase in ultrasonic velocity before CMC is due to the sulphate ions

making hydrogen bond with water molecules. The micelle formation in aqueous

solution of lithium dodecyl sulphate and higher aggregation leads to increase in

velocity after CMC.

The measured ultrasonic velocity increases with increasing

concentration of lithium dodecyl sulphate in aqueous – aprotic solvent (5-20%V/V

of DMSO and DMF) mixtures of solution and exhibits sharp break at a particular

concentration of lithium dodecyl sulphate (i.e.)., CMC as shown in Fig 1 & 2. The

increase in ultrasonic velocity is due to the aprotic solvents act as a structure breaker

in aqueous lithium dodecyl sulphate. Lithium ions are restricting the mobility of the

water molecules. This leads to increase of ultrasonic velocity for before CMC. The

micelle formation in aqueous-aprotic solution of lithium dodecyl sulphate and higher

aggregation leads to increase in velocity before and after CMC of solution. In

addition to dipole moment of DMSO in the solution also contributes increase in

ultrasonic velocity. The velocity observed in aqueous-aprotic solvent at particular

compositions (volume by volume) in the order:

Velocity of DMSO mixture > Velocity of DMF mixture.

From the figures 1 & 2, it is observed that when the 5% V/V of DMSO is

added to the aqueous solution of lithium dodecyl sulphate , the CMC of aqueous

solution of lithium dodecyl sulphate shifted towards the higher concentration side

(8.5 mM). This is due to the lowering of the average dielectric constant of the

medium because of the dielectric constant of water is greater than DMSO.

Similarly, when the 10-20% V/V of DMSO is added to the aqueous solution

of lithium dodecyl sulphate , the CMC of aqueous solution of lithium dodecyl

sulphate shifted towards the higher concentration side in the order of (9.0 mM), (9.4

mM), (9.8 mM), respectively.

All the above explanation is offered for the additive of DMF of various

compositions except the breaking value of CMC. Here, the observed value of CMC

279

is 9.0 mM, 9.4 mM, 9.8 mM and 10.4 mM by addition of 5% of DMF, 10% of

DMF, 15% of DMF and 20% of DMF, respectively. This is due to the difference in

dielectric constant of the DMSO and DMF in these solutions.

Adiabatic compressibility, free length and free volume, internal pressure

studies are supported the ultrasonic velocity studies in aqueous and aqueous aprotic

solvents mixtures.

CONCLUSION

In the present study, the ultrasonic velocity, density, viscosity and internal

pressure increases whereas adiabatic compressibility, free length and free volume

decreases with increasing concentration of lithium dodecyl sulphate in aqueous and

aqueous – aprotic solvent (DMSO & DMF) mixtures. Ultrasonic velocity of DMSO

is slightly higher than DMF for all aqueous and aqueous – aprotic solvent mixtures

because of due to their difference in dipole moment.

The CMC values are obtained in aqueous and aqueous – aprotic solvent

(DMSO and DMF) mixtures of various compositions of concentration of lithium

dodecyl sulphate solutions. The higher CMC values in aqueous – DMF mixtures for

various composition compared to aqueous – DMSO mixtures of various composition

of concentration of lithium dodecyl sulphate. This is due to the average dielectric

constant modification in aqueous – aprotic solvent (DMSO & DMF) mixtures of

lithium dodecyl sulphate.

Figure-1 Figure-2

0.004 0.006 0.008 0.010 0.012 0.014

14951500150515101515152015251530153515401545155015551560156515701575158015851590

Ultr

ason

ic V

eloc

ity(C

) m s

-1

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS

0.004 0.006 0.008 0.010 0.012 0.014

14951500150515101515152015251530153515401545155015551560156515701575

Ultr

ason

ic V

eloc

ity(C

)m s

-1

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

280

Figure-3 Figure-4

Figure-5 Figure-6

Figure-7 Figure-8

0.004 0.006 0.008 0.010 0.012 0.014

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5Vi

scoc

ity()

10-4N

s m

-2

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS 0.004 0.006 0.008 0.010 0.012 0.014

7.0

7.5

8.0

8.5

9.0

9.5

10.0

10.5

11.0

Visc

ocity

() 1

0-4N

s m

-2

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+ 5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

0.004 0.006 0.008 0.010 0.012 0.014

3.9

4.0

4.1

4.2

4.3

4.4

4.5

Adi

abat

ic c

ompr

essi

bilit

y( )1

0-10 m

2 N-1

Molar Concetration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS

0.004 0.006 0.008 0.010 0.012 0.014

3.95

4.00

4.05

4.10

4.15

4.20

4.25

4.30

4.35

4.40

4.45

4.50

Adia

batic

Com

pres

sibi

lity(

) 10-1

0 m2 N

-1

Molar concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

0.004 0.006 0.008 0.010 0.012 0.0140.390

0.395

0.400

0.405

0.410

0.415

0.420

0.425

Free

Len

gth(

L f) 10-1

0 m

Molar Concetration of Lithium Dodceyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS

0.004 0.006 0.008 0.010 0.012 0.0140.395

0.400

0.405

0.410

0.415

0.420

0.425

Free

Len

gth(

L f) 10

-10 m

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

281

Figure-9 Figure-10

Figure-11 Figure-12

References

1) P.G.T. Fogg, J. Chem. Soc., 83, 117 (1958).

2) J. Millar and A.J. Parker J. Am. Chem. Soc., 83, 117 (1961).

3) D.S. Allam and W. N. Lee, J. Chem. Soc., 6049 (1964).

4) S. Nakamura and S. Meiboom, J. Chem. Soc., 89, 1765 (1967).

5) K. Ramabrahaman, Ind.J.Pure.Appl.Phys.6,75 (1968)

6) C.V. Chaturvedi and S. Prakash, Ind. J.Chem.,10,669 (1972)

7) Chanchal Das & Dilip K Hazra Indian J. CHEM vol. 44A,1793(2005).

0.004 0.006 0.008 0.010 0.012 0.0140.80

0.850.90

0.951.001.05

1.101.151.201.25

1.301.35

1.401.451.50

1.551.60

Free

Vol

ume(

V) 1

0-6 m

Molar Concentration of Lithium Dodceyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS

0.004 0.006 0.008 0.010 0.012 0.014

0.90

0.95

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

1.55

1.60

1.0771.0441.0110.9800.9500.9240.9080.9030.8960.891

Free

Vol

ume(

L f) 10

-6 m

-3

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+ 5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

0.004 0.006 0.008 0.010 0.012 0.0148.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

12.5

13.0

13.5

14.0

Inte

rnal

Pre

ssur

e() 1

03 pas

cal

Molar Concentration of Lithium Dodecyl Sulphate

Water+LDS Water+5% DMSO+LDS Water+10% DMSO+LDS Water+15% DMSO+LDS Water+20% DMSO+LDS

0.004 0.006 0.008 0.010 0.012 0.0148.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

12.5

13.0

13.5In

tern

al P

ress

ure(

) 103 p

asca

l

Molar Concentration of Lithium Dodcecyl Sulphate

Water+LDS Water+5% DMF+LDS Water+10% DMF+LDS Water+15% DMF+LDS Water+20% DMF+LDS

282

GROWTH AND CHARACTERIZATION OF BISTHIOUREA MANGANESE

SULPHATE SINGLE CRYSTAL BY SLOW EVAPORATION METHOD

H.POORNIMA

Research Scholar, Department of Physics, Shanmuga Industries Arts & Science College

Tiruvannamalai – 606 601.

ABSTRACT

Bisthiourea Manganese Sulphate crystals were grown by slow evaporation

technique. The grown crystals were characterized by powder x-ray diffraction, it is

confirmed that the synthesized material has characterized nature. The FTIR

spectrosocopic studies were effectively used to identify the functional groups present

in synthesized compound and the molecular structure. From UV-Vis Spectral

Analysis the crystal has a 80% transmission in the entire visible region. The thermal

studied by TGA and DTA techniques were confirms the decomposition of the

sample around 6000C.

1.Introduction

Generally Researchers grow crystals for two main reasons, to understand how

crystals grow (aesthetic) and for the utility (scientific or technological applications of

the grown crystals); for either of these, one must evaluate the quality of the grown

crystals (structural simplicity, symmetry and purity). In recent years, several studies

deal with organic, inorganic and semiorganic molecules and materials due to the

increasing need for cheap and easily processable materials for photonics

applications. Like many metal sulphates, manganese sulphate forms a variety of

hydrates. Non linear optics plays a major role in emerging photonic and

optoelectronics technologies. New non linear optical frequency conversion materials

have a significant impact on laser technology and optical data storage. Thiourea is an

interesting inorganic matrix modifier due to its large dipole moment and its ability to

form an extensive network of hydrogen bonds. It belongs to the orthorhombic crystal

system. However, most of the thiourea complexes crystallize in centro symmetric

form at room temperature. In this present work, manganese sulphate and bisthiourea

crystals were synthesized and characterized by X- ray powder diffract (XRD) ,

283

Fourier Transform Infrared (FTIR), UV- Visible study, Differential and

thermogravimetric analysis (TGA/DTA) and Microhardness techniques.

2.Materials and methods

The BTMS salt was synthesized by dissolving thiourea and manganese sulphate

in molar ratio 2:1 in triple distilled water. The manganese sulphate solution was

added into the thiourea solution. White crystalline salt was formed at the bottom of

the container according to the following reaction.

2 [CS (NH2)2 ] MnSO4 . H2O Mn [CS ( NH2)2 ]2 SO4 H2O

BTMS crystals were grown at room temperature by slow evaporation technique

by dissolving 6g of Manganese sulphate and 19.2g of Thiourea in 100 ml of triple

distilled water under magnetic stirring. The temperature was maintained around

35°C to avoid any decomposition of element from the compound. The resulting

supersaturated solution was filtered for three times using whatmann filter paper. This

filtered solution was poured into Petri dish and it was kept under the observation for

slow evaporation at room temperature.

After a period of 20 days seed crystals were obtained. The photograph of the grown

crystal of BTMS is shown in fig.1.

Fig.1. Photograph of Grown BTMS crystal

X-ray powder diffraction was performed using cu kα radiation (λ=1.54060A0)

to identify the lattice parameters. Fourier transform infrared (FTIR) spectrum of

BTMS crystal was recorded in the range 400–4000 cm-1. The optical absorption

spectra of UCA crystals were recorded in the range of 190 – 1100 nm using Elico SL

218 double beam UV- visible spectrophotometer. Thermal stability and

physiochemical changes of the sample were analyzed by recording the TGA and

DTA spectra in nitrogen atmosphere. The mechanical property of BTMS crystal was

studied by Vickers hardness test.

284

3.Result and discussion

3.1 Powder X-ray diffraction analysis

X-ray powder diffraction analysis of BTMS crystal was carried using X-ray

diffractrometer. The sample was scanned over the range 10 to 700 at a scan rate of

10/min. The indexed powder XRD pattern of the grown crystal (BTMS) is shown in

fig.2. The X-ray diffractometer shows many diffraction peaks. From the sharpness of

the peaks it was conformed that the synthesized material has crystalline nature. From

the result it is observed that the crystal belongs to orthorhombic system with the

following cell dimensions. a=7.6212 Ao ; b=8.5427 Ao ; c=5.5019 Ao and cell

volume V=358.202 A3.

Fig.2. Powder X-ray diffraction analysis of BTMS

3.2 FTIR studies

The FTIR spectroscopic studies were effectively used to identify the functional

groups present in synthesized compound and to determine the molecular structure.

The functional groups of BTMS are confirmed by recording the FTIR spectrum in

the range of 4000-400 cm-1. The Fourier Transform Infrared (FTIR) spectrum of

BTMS is shown in Fig.3. The different functional group of this material are listed in

Table-2. The absorption observed at 3390.24 cm-1 in the spectrum of BTMS

corresponding to the N-H stretching vibration. The vibration observed at 1588.09

cm-1 in the FTIR spectrum is due to N-H bending. . The absorption observed at

3018.05 cm-1 indicates the presence of C-H stretching vibration. The vibration

observed at (872.631 and 727.996) cm-1 indicates the presence of C-H bending.

285

Fig.3. FTIR – Spectral analysis of BTMS

3.3 UV-absorption studies

The optical absorption spectrum of BTMS is shown in Fig.4. The optical

transmittance range and transparency cut off are important in optical applications.

From the UV absorption spectrum, it is evident that BTMS crystal has UV cut off

wavelength at 398 nm, which is an advantage in semi organic non linear optical

materials over their inorganic counterparts. It is well known that an efficient NLO

crystal has an optical transparency lower cut-off wavelength between 200 and 400

nm.

Fig.4. UV-Vis spectral analysis

of BTMS

3.4 Thermal analysis

The thermal stability and physiochemical changes of BTMS crystal were analyzed

by recording the TG–DTA spectrum as shown in Figure 5 & 6. It reveals that BTMS

is thermally stable upto 192°C and after this the sample undergoes appreciable

weight loss. The change in weight loss confirms the decomposing nature of BTMS

sample. The DTA spectrum confirms the melting point of the sample through a sharp

exothermic peak at 185°C. Moreover, the exothermic peak at 242°C reveals the

286

volatile nature of the sample. After that no sharp peak was observed, which confirms

that the material is thermally stable upto 242°C.

Fig.5. TGA Spectral

analysis of BTMS

Fig.6. DTA Spectral

analysis of BTMS

3.5 Vicker’s Micro hardness study

Hardness is a measure of materials resistance to localized plastic deformation. It

plays a key role in device fabrication. Transparent crystals free from cracks were

selected for micro harness measurements. The mechanical property of BTMS crystal

was studied by Vickers hardness test. The applied loads were 10, 25, 50 and 100

grams. The measurement was done at different points on the crystal surface and the

average value was taken as Hv for a given load.

The Vicker’s micro hardness was calculated using the relation

Hv = (1.8544*P)/d2 kg/mm2

Where, Hv is the Vickers micro hardness number, P - is the applied load and d- is the

diagonal length of the indentation impression. The calculated Vickers hardness

values for BTMS crystals as a function of load is shown in figure.7. For BTMS the

maximum hardness 0.080 kg/mm2 is observed for the load 100g. It is concluded that

the sample are materials.

287

Fig.7.Hardness number (Hv) Vs load (P) of BTMS crystal

4. Conclution

Good quality of BTMS crystal is grown by slow evaporation solution growth

method at room temperature. The crystal structure was confirmed by powder X-ray

diffraction study. The presence of various functional groups in the crystal have been

confirmed by using FTIR analysis. UV-Vis study showed that the grown crystal have

good optical transparency. The TG/DTA values of the crystal were determined the

melting point of the grown crystal and finally the Vickers microhardness studies

have been carried out.

References

1. Jiang,M.H.,Fang,q.(1999).advance materials

2. Ram S,J Magn Magn Matter,80 (1989)

3. Sing p, Babber V K, Razton A, Goel T C, Srivastsava I C, Indian J Appl

physics 42 (2004)

4. Saima J,Gruokova A, Papanova M.J Elect Eng 56 (2005)

5. L. Bellamy, The Infrared Spectra of Complex Molecules; Wiley: New York,

1958

6. Laura Cecilia Bichara, Hernan Enrique Lanus, Evelina Gloria Ferrer, Monica

Beatriz Gramajo, Silvia Antonia Brandan, Advan. Phys. Chem., 2011

7. Y. Le Fur, R. Masse, M.Z. Cherkaoui, J.F. Nicoud, Z. Kristallogr. 1993

8. S.M. RaviKumar, N.Melikechi, S.Selvakumar, P.Sagayaraj, J. Cryst. Growth,

2009

288

Growth and physicochemical properties of a new semiorganic nonlinear optical

material thiourea potassium hydrogen phthalate for NLO applications

A.Anbarasi1, R.Srineevasan2, M. Packiyaraj3 and S.M.Ravi Kumar2*

1Department of Physics, Periyar Government Arts College, Cuddalore 2PG & Research Department of Physics, Government Arts College, Tiruvannamalai

3Department of Physics, S.K.P. Engineering College, Tiruvannamalai

ABSTRACT

Thiourea potassium hydrogen phthalate (TKHP), a semiorganic nonlinear

optical single crystal is grown by slow evaporation solution growth technique at

room temperature. The Single crystal XRD reveals that the grown crystal is an

orthorhombic system. UV–visible NIR spectral study confirms the transmission

band of 100% in the range 200 – 900 nm with enhanced lower cutoff wavelength.

Thermal stability of TKHP was found to be 305.1°C. The second harmonic

generation (SHG) efficiency of TKHP is observed by the Kurtz powder technique.

1. Introduction

In recent years semiorganic complexes have attracted the researcher owing to

their applications in second and higher harmonic generations, optical bistability,

laser remote sensing, optical disc data storage, laser driven fusion, medical and

spectroscopic image processing, color display and optical communication [1,2].

Due to lack of extended π-electron delocalization and hence moderate optical

nonlinearity, low laser damage threshold, low optical transparency, lack of quality

and bulk size are the major limitations in organic nonlinear optical (NLO) crystals.

Hence, the research scientist focusing on new kind of crystals called semiorganic

crystal. In semiorganic, stoichiometric bond is between inorganic and organic

molecules gives the advantage of combined properties such as high optical

nonlinearity, extended transparency region-down to UV, promising crystal growth

characteristics, chemical inertness and good mechanical hardness [3]. To get the

strong mechanical and high thermal stabilities in semiorganics, cation of hydrogen

bonded nonlinear organic molecules are linked to the anion of inorganic molecules

as an acid–base interaction [4]. Highly delocalized π-electrons induces molecular

charge transfer in semiorganics, which make π-electrons easily move between

electron donor and electron acceptor groups on opposite sides of the molecule [5,6].

289

Noncentrosymmetric potassium hydrogen phthalate semiorganic crystal (KHP) is a

mono-potassium salt of phthalic acid, widely used in the field of X-ray spectroscopy

as monochromator, substrate for the deposition of thin films organic NLO materials

and analyzer with optical, piezoelectric and elastic properties (7-10). KHP is

slightly acidic, dissociates completely in water, giving the potassium cation (K+)

and hydrogen phthalate anion (HP−). Paring of dipole moment in parallel fashion of

potassium acid phthalate is established by the bonding energy present in the

hydrogen bonds linkage between acid–base interactions and hence enhanced value

of SHG activity reported [11–14].

Thiourea, less extensively delocalized organic and coplanar in structure,

exhibit mesomeric effects which are responsible for second harmonic generation

(SHG) in the blue-near-UV regions [15]. Thiourea complexes show high optical

nonlinearity with flexibility and physical hardness like organic and inorganic

materials respectively. In the present study, growth of thiourea potassium hydrogen

phthalate (TKHP) crystals by slow evaporation solution growth technique and its

physico-chemical properties have been discussed and which have not found in the

literature.

2. Experimental Procedure

2.1 Synthesis

TKHP salt was synthesized at room temperature by taking analytical grade

thiourea and potassium hydrogen phthalate in 1:1 stoichiometric ratio with Millipore

water as a solvent of 18.2 mΩ cm resistivity. The synthesized TKHP salt has been

obtained by the following chemical reaction and their reactants and product are

shown in Scheme 1. Stacking of TKHP crystal one over the other is shown in

Scheme 2.

[(NH2)2SC] + C8H5KO4 → [(C8 H4O3K)∙(NH)(NH2) SC

+.H2O]

(Thiourea + Potassium hydrogen phthalate → TKHP crystal)

290

Scheme 1. Molecular arrangement of TKHP crystal

2.2 Crystal Growth

The synthesized solutions were stirred vigorously at room temperature for 4h

using motorized magnetic stirrer. Continuous stirring with temperature 5°C greater

than room temperature ensures homogeneous mixing of solutions. Purification of the

synthesized salt was achieved by successive recrystalization process. The saturated

solution was filtered with watman filter paper of micron pore size and this

synthesized clear solution was poured into a petri dish and covered with pores paper

for slow evaporation of the solvent. After a span of two weeks the solvent was

evaporated and good quality TKHP crystals of size 5mm x 4mm x 3mm were

harvested from the Petri dishes. The grown crystal was defect less and optically

transparent with no inclusions. As-grown crystal TKHP is shown in figure 1. In this

acid-base interaction polarizable cation (K+) of noncentrosymmetrical system,

derived from potassium hydrogen phthalate linked to the thiourea through a

hydrogen bond network. In this complex TKHP, Sulphur atoms of thiourea

coordinated through Potassium atom of potassium hydrogen phthalate molecule and

the carbon atom in thiourea bonds with one sulphur and two nitrogen atoms.

Formation of water molecules facilitates, bond between one amino group hydrogen

to hydroxyl group of potassium hydrogen phthalate.

291

Figure 1 As-grown crystal of TKHP by slow evaporation technique

3. Characterizations of TKHP crystal

X- ray diffraction studies of the grown crystal were obtained on a PHILIPS

XPERT MPD system. The grown crystal of TKHP was subjected to absorption study

by using LAMBDA-35 UV-vis Spectrometer. Thermo gravimetric and differential

thermal analysis were carried out on NETZSCA STA 409 instrument heating rate of

20°C min-1 from 50°C to 500°C. The SHG efficiency of the grown crystal was

measured by KURTZ and PERRY powder technique using ND: YAG laser of

wavelength 1064nm.

4 Results and discussion

4.1 Single Crystal XRD Studies

The single crystal XRD study confirms the unit cell parameters of the TKHP

crystals a=6.439Å; b=9.565Å; c=13.241Å; α = β = γ = 90˚; and the volume of the

unit cell is found to be 815Å3.. Hence the result shows that TKHP species belong to

orthorhombic crystal system.. Same values of α, β and γ of TKHP indicates that there

is no change in orthorhombic crystal systems due to thiourea in potassium hydrogen

phthalate crystals (α=β=γ=90˚). Small change in the cell volume of TKHP (815Å3)

compared with KHP (861Å3).This analysis indicates that the addition of thiourea

ligand in the potassium hydrogen phthalate crystal does not change the crystal

structure though there is a small change in lattice parameters.

5 mm

4 m

m

292

10 20 30 40 50

0

100

200

300

400

500

600

700

800

900

(002

) (011

)

(012

)

(111

)(1

12)

(020

) (021

)(1

20)

(201

) (210

)(1

22)

(023

)

(123

)(0

15) (221

)

(132

)

(106

)(2

05)

(034

)(2

31) (232

)(3

20)

(141

)

KHA + Thiourea

Inte

nsity

(a.u

)

2 (degree)

200 300 400 500 600 700 800 900

0

1

2

3

4

5

Abs

orba

nce

(a.u

)

Wavenumber (nm)

4.2 Powder XRD studies

Powder x-ray diffraction study of TKHP crystal is shown in Fig 2. From the

XRD pattern, the observed sharp and well defined peaks without any broadening

confirm the grown sample is in good crystalline nature.

Figure 2 Powder XRD of grown

TKHP crystal

4.3 UV- Visible spectrum analysis

The selective electronic absorption spectrum of TKHP crystal recorded in the

range 200 -900 nm is shown figure 3. Optically polished single crystal of thickness 3

mm was used for this study. The recorded absorption spectrum, UV and Visible light

promote electrons in σ and π orbital from ground state to a higher energy state with a

limited introduction about the structure of the molecule. The absorption spectrum

shows the grown crystal has a lower cutoff wavelength at 290 nm, that attributes the

electronic transitions in the aromatic ring of TKHP crystals. Absence of absorbance

in the region between 290 nm to 900 nm is an essential property of the NLO

materials. The grown TKHP crystal has transparency close to 100% in the UV-

Visible and IR region and hence, the crystal can be used as a sensor material for UV,

Visible and in the IR regions.

This wide range of

transparency close to 100%

transmission shows that the

grown TKHP crystal is a

potential candidate for the

optoelectronic applications

[22].

Figure 3 UV-Visible-NIR absorption spectrum of as-grown TKHP crystal

293

4.4 Thermal studies

TGA and DTA curves of TKHP crystal are shown in figure 4. Crystal samples

were weighed in an Al2O3 crucible with temperature control facility. Thermo-

gravimetric (TG) /differential thermal (DT) analysis curves between ambient

temperatures to 500˚C of TKHP crystals recorded in nitrogen atmosphere were

shown in figure 5. The DTA curve of TKHP crystal shows two stage

decompositions. First stage decomposition was observed between 275°C to 340°C

with the exact decomposition temperature at 305.1°C.

Figure 4 TG&DTA curves of as-grown TKHP crystal

As a second stage, the decomposition temperature lies at 442.4°C in the range

430- 455°C. No weight loss between 50°C and 137.6°C indicates, that there is no

inclusion of solvent in the as grown TKHP crystal lattice, which was used for

crystallization. DTA endothermic peak shows melting point of as-grown TKHP

crystal at 305.1°C. The TG spectrum reveals that the gradual weight loss starts at

137.6°C [2.568mg-0.0%] and at 183.6°C it is about 2.538mg (Loss:1.2%);

continuous up to 245.7 °C [2.531mg-1.75%]. The Major weight loss occurs between

245.7°C and 321°C and 1.506 mg (39.8%) was obtained as a residue. This nature of

weight losses indicating the decomposition of the material and after 321°C no weight

loss was observed. This was compared with the decomposition point of potassium

hydrogen phthalate (KHP) crystal 298°C [16].

294

4.5 NLO studies

To confirm NLO property of the TKHP crystal, powdered form of the grown

crystals were subjected to KURTZ and PERRY techniques, which is the powerful

tool for initial screening of materials for second harmonic generation [17]. The beam

of fundamental wave length λω =1064 nm (incident beam wave power Pω) from Q-

switched Nd: YAG laser was made to fall normally on the powder form crystal

sample, which was packed between two optically transparent glass slides. Here

standard KDP has taken as a reference material. The SHG behavior of the TKHP

sample was confirmed by emission of bright green radiation wavelength λ=532nm of

power P2ω. The measured amplitude of second harmonic green light of TKHP crystal

was 10.8 mJ against 8.8 mJ for KDP crystal. The powder SHG efficiency of TKHP

crystal is about 1.2 times of KDP. Enhancement of SHG efficiency in TKHP crystal

is due to the stoichiometric addition of thiourea in potassium hydrogen phthalate,

facilitate molecular charge transfer and alignment of dipole moment in a parallel

manner. This enhanced SHG efficiency indicates, that the grown TKHP crystals can

effectively replace conventional nonlinear optical devices.

4. Conclusion

Good optical quality crystals of thiourea potassium hydrogen phthalate

(TKHP) were grown by the slow evaporation technique with the dimension size

5mm x4mm x3mm. Powder XRD study reveals, that the grown TKHP crystal is in

good crystalline nature. From single crystal XRD study orthorhombic systems of the

grown crystal are confirmed. UV–visible absorption spectral study shows wide

range of transmission bands (100%) with lower cutoff wavelength 290 nm..TGA and

DTA spectral analysis confirms the thermal stability of the grown crystals. Second

harmonic generation study of the grown TKHP crystal shows that, it is having NLO

property and their SHG efficiency is greater than standard KDP.

References

[1] Santhanu Bhattucharya, Parthasarathi, T.N. Guru Row, Chem. matter. 6 (1994)

531-537.

[2] Y.J.Ding, X.Mu, X.Cu, J. Nonlinear Opt. Phy. Matter. 9 (2000) 21.

295

[3] N.Karthick,R.Sankar,R.Jayavel,S.Pandi, J.Cryst .Growth, 312 (2009) 114-119.

[4] C.B. Aakeroy, P.B. Hitchcock, B.D. Moyle, K.R. Seddon, J. Chem. Soc., Chem.

Commun. (1992) 553-555.

[5] Ch.Bosshard, K.Sutter, Ph.Pretre, J.Hulliger, M.Florsheimer, P.Kaatz, P.Gunter,

organic Nonlinear optical materials, Gordon and Breach, Basel, 1995.

[6] M.C. Etter, J. Chem. Phy. 95 (1991) 4601-4610.

[7] L.M. Belyaev, G.S. Belikova, A.B. Gilvarg, I.M. Silvestrova, Sov. Phys.

Crystallogr.14 (1970) 544-.

[8] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal Growth 78 (1986) 379-388.

[9] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal. Growth, 91 (1988) 623-631.

[10] M.H.J. Hottenhuis, C.B. Lucasius, J. Crystal Growth 94 (1989) 708-720.

[11] S. Debrus, H. Ratajczak ,J. Venturini, N. Pincon ,J. Baran, J. Barycki,T.

Glowiak, A. pietraszko, Synthetic Metals 127 (2002) 99-104.

[12]Y.Lefur, M.Bagiue-Beucher, R.Masse, J.F.Nicoud, J.P.Levy, Chem.Mater. 8,

(1996) 68-71.

[13] H.Ratajczak, J.Baran, J.Barycki, S.Debrus, M.May, A.Pietraszko,

H.M.Ratajczak, A.Tramer, J.Venturini, J.Mol.Struct. 555 (2000) 149-158.

[14] H. Ratajczak, S. Debrus, M. May, J. Barycki, J. Baran, Bull. Pol. Acad. Sci.

Chem. 48 (2000) 189-192.

[15] P.R. Newman, L.F. Warren, P. Cunningham, T.Y.Chang, D.E. Copper, G.L.

Burdge, P. Polak dingles., C.K. Lowe-Ma, Advanced Organic Solid State

Materials, 173 (1990) 557-561.

[16]M. Oussaid, P. Becker, M.C. Kemiche, Carabatos-Nedlec, Phs. Stat. Sol. B 207

(1998) 103-110.

[17] S.K.Kurtz, J.J.Perry, J. Appl. Phys, 39 (1968) 3798-38136.

296

SOLUTION OF COUPLED NONLINEAR EQUATION BY

VARIATIONAL ITERATION METHOD

M.Sudhalakshmi1, R.Sivakumar2 1 Department of Physics, Shanmuga Industries Arts and Science College,

Tiruvannamalai District- 606601, Tamil Nadu 2 Department of Physics, Pondicherry University, Pondicherry - 605 014

ABSTRACT

It is shown in this paper one of the recently developing analytical techniques

viz., the Variational iteration method (VIM) to a special kind of nonlinear

differential equations. Variational iteration method (VIM) does not require any

linearization procedures to solve the

PDEs under consideration and also no computing facilities are needed. The results

show that this method gives reasonably accurate values compared with analytical

solution even with two iterations itself.

Key words: Analytical solution; Variational iteration method; Nonlinear equation

1. INTRODUCTION

Nonlinear partial differential equations (NLPDE) are widely used to describe

complex phenomena in various fields of science, especially in physics. Numerical

methods such as finite difference or characteristics method need a large amount of

computation and the effect of round-off error which causes the loss of accuracy. In

the last two decades with the rapid development of nonlinear science, there has

appeared ever increasing interest of scientists and engineers in the analytical

techniques. The investigation of exact solution of NLPDE’s plays an important role

in the study of nonlinear physical phenomena. Burger's equation [1, 22] is a useful

model equation which governs shock wave, acoustic transmission, traffic and

aerofoil flow theory, turbulence and supersonic flow as well as a prerequisite to the

Navier-Stokes equations. Burgers equation is a proper model for testing numerical

algorithm in flows. It is a useful model equation applied to complicated fluid flow

problems and interesting challenge for the control design. Analytical methods for

solving Burger's equation are very restricted and can be used in very special cases; so

they cannot be used to solve equations of numerous realistic scenarios. VIM is one

297

such analytical technique. He's variational iteration method is a powerful device for

solving functional equations.

2. HE'S VARIATIONAL ITERATION METHOD

He [7]-[17] has recently attracted a great deal of attention for solving easily and

efficiently a number of nonlinear functional equations. The main feature of the

proposed Variational Iteration Method [9, 25] is the solution of a mathematical

problem with linearization assumption is used as initial approximation (trial-

function), and then a more highly precise approximation at some special point can be

obtained. Variational iteration method (VIM) [14] is uniquely qualified to address

this challenge; the flexibility and adaptation provided have made the method a strong

candidate for approximate analytical solution and wide applications in various fields.

It provides physical insight into the nature of the solution of the problem and finds

accurate solution among all the possible trial-functions. He's method turns the

functional equation into a recurrence sequence of functions is the exact solution.

The keystone of the VIM is a generalized Lagrange multiplier determined by

stationary conditions imposed on an appropriate correction functional. The

convergence VIM is systematically discussed by Tatari and Dehghan.

z)y,x,g(t, Nu (u)L (u)L (u)L (u)L zyxt (1)

we constructs the correction functional as,

,0,0

~

1

ndssgsuNsLustutu

t

nnnn (2)

where general Lagrange multipliers can be identified via variational theory, the

nonlinear term and the analytical function usually taken as correction. He [8]-[17]

took the non linear term as restricted so as to find the approximate Lagrange

multiplier which helps in solving the equation to get the exact solution. The variation

operator on the restricted variation term leads to zero i.e 0~nu .. The subscript n

denotes the nth-order approximation.

3. COUPLED NONLINEAR EQUATIONS

3.1. ONE DIMENSIONAL TIME DEPENDENT COUPLED BURGER

EQUATION.

298

(3)

(4)

are subjected to the following initial conditions:

xxu sin)0,( (5)

xxv sin)0,( (6)

After constructing correction function and applying calculus of variation on both

sides we get

of 3 and 4 we have,

Where, 21 are general Lagrange multipliers and are ~

nxn uu ,~

nxn vv ,x

nn vu

~

restricted

variations i.e. 0~~~

xnnnxnnxn vuvvuu .

Applying He's calculus of variation we get,

dututtyxu n

t

tntn 0

'111 //)(1),,(

dvtvttyxv n

t

tntn 0

'221 //)(1),,(

Stationary conditions thus obtained as,

(7)

299

(8)

Lagrange multipliers 21, are

(9)

(10)

Substituting Lagrange multipliers and 0n the iteration equations is as follows,

(11)

(12)

start with the arbitrary initial approximation that satisfies the initial conditions

xxu sin)0,( (13)

xxv sin)0,( (14)

Using 13 and 14 in 11 and 12 gives,

xtxtxu sinsin),(1 (15)

xtxtxv sinsin),(1 (16)

Substituting Lagrange multipliers and 3,2,1 nnn the second, third and fourth

iteration equations are as

xtxtxtxu sin2

sinsin),(2

2 (17)

xtxtxtxv sin2

sinsin),(2

2 (18)

xtxtxtxtxu sin3*2

sin2

sinsin),(32

3 (19)

xtxtxtxtxv sin3*2

sin2

sinsin),(32

3 (20)

xtxtxtxtxtxu sin!4

sin!3

sin!2

sinsin),(232

4 (21)

300

xtxtxtxtxtxv sin!4

sin!3

sin!2

sinsin),(232

4 (22)

Extending this iteration, we can show that

...sin!4

sin!3

sin!2

sinsin),(232

xtxtxtxtxtxu

=

...

!4!3!21sin

232 ttttx

= xt sin)exp( (23)

...sin!4

sin!3

sin!2

sinsin),(232

xtxtxtxtxtxv

=

...

!4!3!21sin

232 ttttx

= xt sin)exp( (24)

We now calculate the numerical results of the solution of one dimension coupled

time dependent Burger equation 3 and 4 using equations 21 and 22. These values are

compared with 23 and 24. The error in the solutions obtained by Variational Iteration

Method is the absolute difference between analytical values and equations 3 and 4.

They are tabulated in table 1, from the table we

observed that the absolute error is smaller for least t values. x for different values

of t for ),(4 txu is shown in figure 1. Proceeding with higher iterations we can

increase the accuracy of the numerical solution.

Table 1: Numerical results for ),(4 txu or ),(4 txv of one dimension time dependent coupled

Burger equation in comparison with the analytical solution

t x Exact solution VIM solution Absolute error

0.1 0.090333010952424 0.090333019135174 -0.0818e-007

0.2 00.179763444319535 0.179763460603276 -0.1628e-007

0.3 0.267397740772900 0.267397764994930 -0.2422e-007

0.4 0.352360287390403 0.352360319308704 -0.3192e-007

0.1

0.5 0.433802166491126 0.433802205786781 -0.3930e-007

301

0.6 0.510909637740202 0.510909684020580 -0.4628 e-007

0.1 0.081736688393606 0.081736945989313 -0.0818e-007

0.2 0.162656690815339 0.162657203432943 -0.1628e-007

0.3 0.241951481349599 0.241952243867194 -0.2422e-007

0.4 0.318828772660741 0.318829777459502 -0.3192e-007

0.5 0.392520432266236 0.392521669306548 -0.3930e-007

0.2

0.6 0.462290157462532 0.462291614384295 -0.4628 e-007

0.1 0.073958414084880 0.073960338805095 -0.0192e-004

0.2 0.147177860143625 0.147181690352886 -0.0383e-004

0.3 0.218926753674347 0.218932451102470 -0.0570e-004

0.4 0.288488203449919 0.288495711170085 -0.0751e-004

0.5 0.355167174458140 0.355176417455691 -0.0924e-004

0.3

0.6 0.418297432461834 0.418308318383795 -0.1089e-004

0.1 0.066920340442597 0.066928322520034 -0.0798e-004

0.2 0.133172034964415 0.133187919365009 -0.1588e-004

0.3 0.198093118533691 0.198116746545762 -0.2363e-004

0.4 0.261034921143457 0.261066056683719 -0.3114e-004

0.5 0.321368549107831 0.321406881080258 -0.3833e-004

0.4

0.6 0.378491168759837 0.378536314164032 -0.4515e-004

Figure 1: Solution of obtained ),(4 txu by VIM versus x for different values of

time

302

3.2 TWO DIMENSIONAL BURGER EQUATION

(25)

(26)

where Re is the Reynolds number and subjected to the following initial conditions:

(27)

(28)

and

After constructing the correction function we get the Lagrange multipliers as

Applying He's calculus of variation, the iteration equations are as

dvuuvuuutyxutyxut

nyynxxnynnxnnnn

0

~~

1 )(Re1),,(,,

(29)

dvvvvvuvtyxvtyxvt

nyynxxnynnxnnnn

0

~~

1 )(Re1),,(,,

(30)

We start with the arbitrary initial approximation that satisfies the initial conditions

and substituting 0n in 29 and 30 the first iteration equations are,

303

te

ee

tyxu 211128

Re)1(4

143),,(

(31)

te

ee

tyxv 211128

Re)1(4

143),,(

(32)

To get the second iteration we put 1n 1 in 29 and 30

We now calculate the numerical results of the solution of two dimensional coupled

homogeneous Burger equation 25 and 26 using equations 33 and 34.These values are

compared with analytical solutions given by

304

The error in solutions obtained by Variational Iteration Method is the absolute

difference between analytical values and 33 and 34. They are tabulated in Tables 2,

3. From these tables we observe that the absolute error is smaller than 610 even for

second iteration. To improve or reduce the error, we have to proceed with higher

iterations which becomes more complicated.

Table 1: Numerical results for ),,(2 tyxu 25 obtained by VIM method for Re = 100

at y = 1 in comparison with analytical solution

t x Exact solution VIM solution Absolute

error

0.1 0.749995555362034

0.749994383449127 -1.1719e-

006

0.2 0.749984487375994

0.749980397293144 -4.0901e-

006

0.3

0.749945863987526 0.749931591790085

-1.4272e-

005

0.4 0.749811148591818

0.749761377483330 -4.9771e-

005

0.5

0.749342081506279 0.749168894884322

-1.7319e-

004

0.1

0.6 0.747718590652705

0.747120525817792 -5.9806e-

004

0.1 0.749993924939814

0.749991314568159 -2.6104e-

006

0.2 0.749978797239569

0.749969686748774 -9.1105e-

006

0.3 0.749926010721622

0.749894219312531 -3.1791e-

005

0.4

0.749741942240811 0.749631068604713

-1.1087e-

004

0.2

0.5 0.749101599354645

0.748715700340454 -3.8590e-

004

305

0.6 0.746892087286704

0.745558428188497 -1.3336e-

003

0.1 0.749991696451263

0.749987560789737 -4.1357e-

006

0.2

0.749971020164203

0.749956585568673

-1.4435e-

005

0.3 0.749898879625539

0.749848501385006 -5.0378e-

005

0.4 0.749647410375845

0.749471615822517 -1.7579e-

004

0.5 0.748773648573570

0.748160618831361 -6.1303e-

004

0.3

0.6 0.745771271683318

0.743639619092962 -2.1316e-

003

0.1 0.749988650532824

0.749983329906607 -5.3206e-

006

0.2 0.749960390945224

&0.749941817339808 -1.8574e-

005

0.3 0.749861805340769

0.749796943162410 -6.4862e-

005

0.4 0.749518316334168

0.749291517140896 -2.2680e-

004

0.5 0.748326787268929

0.747530433123219 -7.9635e-

004

0.4

0.6 00.744255657522494

0.741427052666243 -2.8286 e-

003

0.1 0.749984487375994

0.749979183188871 -5.3042e-

006

0.2 0.749945863987526

0.749927335866920 -1.8528e-

005

0.5

0.3 0.749811148591818

0.749746300778153 -6.4848e-

306

005

0.4

0.749342081506279 0.749113594321782

-2.2849e-

004

0.5

0.747718590652705 0.746896033502150

-8.2256e-

004

0.6 0.742214042366305

0.739079589133349 -3.1344e-

003

0.1 0.749978797239569

0.749976306431121 -2.4908e-

006

0.2 0.749926010721622

0.749917265736494 -8.7450e-

006

0.3 0.749741942240811

0.749710798008835 -3.1144e-

005

0.4 0.749101599354645

0.748985437415671 -1.1616e-

004

0.5 0.746892087286704

0.746400296384409 -4.9179e-

004

0.6

0.6

0.739478068021095 0.736877431048402

-2.6006e-

003

Table 1: Numerical results for ),,(2 tyxv 26 obtained by VIM method for Re = 100

at y = 1 in comparison with analytical solution

t x Exact solution VIM solution Absolute error

0.1 0.750004444637966 0.750005616550873 1.1719 e-006

0.2 0.750015512624006 0.750019602706856 4.0901e-006

0.3 0.750054136012474 0.750068408209915 1.4272 e-005

0.4 0.750188851408182 0.750238622516670 4.9771 e-005

0.5 0.750657918493721 0.750831105115678 1.7319 e-004

0.1

0.6 0.752281409347295 0.752879474182208 5.980 e-004

0.1 0.750006075060186 0.750008685431841 2.6104e-006 0.2

0.2 0.750021202760431 0.750030313251226 9.1105e-006

307

0.3 0.750073989278378 0.750105780687469 3.1791e-005

0.4 0.750258057759189 0.750368931395287 1.1087e-004

0.5 0.750898400645355 0.751284299659546 3.8590e-004

0.6 0.753107912713296 0.754441571811503 1.3336e-003

0.1 0.750008303548737 0.750012439210263 4.1357e-006

0.2 0.750028979835797 0.750043414431327 1.4435e-005

0.3 0.750101120374461 0.750151498614994 5.0378e-005

0.4 0.750352589624155 0.750528384177483 6.1303e-004

0.5 0.751226351426430 0.751839381168639 1.7579e-004

0.3

0.6 0.754228728316682 0.756360380907038 2.1316e-003

0.1 0.750011349467176 0.750016670093393 5.3206e-006

0.2 0.750039609054776 0.750058182660192 1.8574e-005

0.3 0.750138194659231 0.750203056837590 6.4862e-005

0.4 0.750481683665832 0.750708482859104 2.2680e-004

0.5 0.751673212731071 0.752469566876781 .9635e-004

0.4

0.6 0.755744342477506 0.758572947333757 2.8286e-003

0.1 0.750015512624006 0.750020816811129 5.3042e-006

0.2 &0.750054136012474 0.750072664133080 1.8528e-005

0.3 0.750188851408182 0.750253699221847 6.4848e-005

0.4 0.750657918493721 0.750886405678218 2.2849e-004

0.5 0.752281409347295 0.753103966497850 8.2256e-004

0.5

0.6 0.757785957633695 0.760920410866651 3.1345e-003

0.1 0.750021202760431 0.750023693568879 2.4908e-006

0.2 00.750073989278378 0.750082734263506 8.7450e-006

0.3 0.750258057759189 0.750289201991165 3.1144e-005

0.4 0.750898400645355 0.751014562584329 1.1616e-004

0.5 0.753107912713296 0.753599703615591 4.9179e-004

0.6

0.6 0.760521931978905 0.763122568951598 2.6006e-003

308

4. CONCLUSION

In this work, we have reviewed available literature, of numerical and analytical

methods on solving PDE's. We have selected one of the available analytical method

called Variational Iteration Method. We have applied VIM to solve various forms of

Burger equation. From the solutions we find that even with a very few iterations one

can get reasonably accurate solutions as we seen in the Tables 1, 2, 3. This indicates

that VIM is a powerful technique to find analytical solutions of PDE's. Extending

VIM method to coupled and nonlinear PDE's is still difficult since we have to start it

with an initial solution which is not known a priori.

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311

ULTRASONIC STUDIES ON THE EFFECT OF DIOXANE AND

TETRAHYDROFURAN ON THE MICELLIZATION

OF CETYL TRIMETHYL AMMONIUM BROMIDE

IN AQUEOUS SOLUTIONS

G. Lakshiminarayanan1 and D.Sakthivel2

1,2 Department of Physics, Shanmuga Industries Arts and Science College,Thiruvannamalai.

ABSTRACT

Ultrasonic velocity, density and viscosity studies have been carried out in

aqueous solutions of cetyl trimethyl ammonium bromide (CTAB) and in aqueous

solutions of CTAB containing 5-20% V/V of dioxane (DN), tetrahytrofuran (THF).

These studies are carried out in CTAB concentration of 0.5mM to 5mM at a fixed

frequency of 2MHz and at a fixed temperature of 303.15K. The variation of

ultrasonic velocity in aqueous solutions of CTAB containing 5-20% V/V of DN

and THF with CTAB concentration exhibiting a break at critical micelle

concentration (CMC). The ultrasonic velocity, adiabatic compressibility, free length,

free volume and internal pressure also exhibiting a break at CMC similar to velocity

curve. The results are discussed in terms of formation of CTAB micelles through

hydrophobic interaction and hydrogen bonding.

INTRODUCTION

Molecular interaction in liquid mixtures has been the subject of

numerous investigation in recent past years [1-6].The systems shows a wide verity of

physical properties. Resent researchers have studied the interaction of cetyl trimethyl

ammonium bromide (CTAB) with alcohol through ultrasonic techniques [7]. But the

effect of aprotic solvent on CTAB is scandy. The aim our present investigation is to

determine ultrasonic studies on the effect of dioxane and tetrahydrofuran on

the micellization of cetyl trimethyl ammonium bromide in aqueous solutions at

fixed frequency of 2 MHz and fixed temperature of 303.15 k. The results are

interpreted in terms of formation of CTAB micelles in the solutions.

MATERIALS AND METHODS

The cetyl trimethyl ammonium bromide (CTAB) used in the present study are

of AR/BDH grade purchased from SD-fine chemicals Ltd., India and they are used

312

as such without further purification. The solvents used namely Dioxane and

tetrahydrofuran are of spectroscopic grade. Triply distilled deionised water is used

for preparing the solutions of CTAB. Ultrasonic velocity studies are carried out at a

fixed frequency of 2 MHz in the cetyl trimethyl ammonium bromide concentration

range of 0.5mM to 5mM. Ultrasonic velocity is measured using a Digital Ultrasonic

Velocity meter (Model VCT-70A, Vi-Microsystems Pvt. Ltd., Chennai, India) at a

fixed temperature at 303.15K by circulating water from a thermostatically controlled

water bath and the temperature being maintained to an accuracy of ±0.1oC. The

accuracy in measurement of velocity and absorption is ±2 parts in 105 and 3%

respectively. Shear viscosity and density of aqueous solutions of CTAB containing

5-20% V/V of DN and THF are determined using an Oswald’s viscometer and a

graduated dilatometer respectively. The accuracy in measurement of density and

viscosity is ±2 parts in 104 and ± 0.1% respectively. From the measured values of

ultrasonic velocity, density and viscosity, the various other parameters such as

adiabatic compressibility (βs), intermolecular free length (Lf), free volume (Vf ) and

internal pressure (Пi) are calculated using standard formulae.

COMPUTATIONS OF PARAMETERS

Adiabatic compressibility (βs), intermolecular free length (Lf), free volume

(Vf) and internal pressure (Пi) were estimated using the equations (1- 4),

respectively.

βs = 1/C2ρ (1)

Lf = KT βs 1/2 (2)

Vf = (M C / K η)3/2 (3)

πi = bRT (K η / C)1/2 (ρ2/3/ M7/6) (4)

where, c is ultrasonic velocity, ρ is density, KT is temperature dependant constant, M

is effective molecular weight, K is constant for liquids, b is constant, T is

temperature.

RESULT AND DISCUSSIONS

From the measured values of density, ultrasonic velocity and viscosity,

the other parameters such as adiabatic compressibility, free length, free volume and

313

internal pressure were computed and shown in graphically in figures (1-12).The

variations of ultrasonic velocity against concentration of Cetyl Trimethyl

Ammonium in aqueous solution are given in Figs. 1 & 2. The measured ultrasonic

velocity increases with increasing concentration of Cetyl Trimethyl Ammonium

bromide in aqueous solutions and exhibits sharp break at a particular concentration is

known as Critical Micellar Concentration (CMC), which is confirmed by Ionescu et

al [8]. The increase in ultrasonic velocity before CMC is due to the bromide ions

making hydrogen bond with water molecules. The micelle formation in aqueous

solution of Cetyl Trimethyl Ammonium bromide and higher aggregation leads to

increase in velocity after CMC.

The measured ultrasonic velocity increases with increasing

concentration of Cetyl Trimethyl Ammonium bromide in aqueous – aprotic solvent

(5-20%V/V of Dioxane and Tetrahydrofuran) mixtures of solution and exhibits sharp

break at a particular concentration of Cetyl Trimethyl Ammonium bromide (i.e.).,

CMC as shown in Fig 1 & 2. The increase in ultrasonic velocity is due to the aprotic

solvents act as a structure breaker in aqueous Cetyl Trimethyl Ammonium bromide.

Cetyl Trimethyl Ammonium ions are restricting the mobility of the water molecules.

This leads to increase in ultrasonic velocity for before CMC.The micelle

formation in aqueous-aprotic solution of Cetyl Trimethyl Ammonium bromide and

higher aggregation leads to increase in velocity for after CMC of solution. In

addition to dipole moment of dioxane in the solution also contributes increase in

ultrasonic velocity. The velocity observed in aqueous-aprotic solvent at particular

compositions (volume by volume) in the order:

Velocity of THF mixture > Velocity of Dioxane mixture.

From the figures 1 & 2, it is observed that when the 5% V/V of Dioxane is

added to the aqueous solution of Cetyl Trimethyl Ammonium Bromide, the CMC of

aqueous solution of Cetyl Trimethyl Ammonium bromide shifted towards the higher

concentration side (3 mM). This is due to the lowering of the average dielectric

constant of the medium because of the dielectric constant of water is greater than

dioxane.

Similarly, when the 10-20% V/V of dioxane is added to the aqueous solution

of Cetyl Trimethyl Ammonium Bromide, the CMC of aqueous solution of Cetyl

314

Trimethyl Ammonium Bromide shifted towards the higher concentration side in the

order of (3.5 mM), (4.0 mM), (4.5 mM), respectively.

All the above explanation is offered for the additive of Tetrahydrofuran of

various compositions except the breaking value of CMC. Here, the observed value

of CMC is 2.5 mM, 3.0 mM, 3.5 mM and 4.0 mM by addition of 5% of THF, 10%

of THF, 15% of THF and 20% of THF, respectively. This is due to the difference in

dielectric constant of the dioxane and tetrahydrofuran in these solutions.

Adiabatic compressibility, free length and free volume, internal pressure

studies supports the ultrasonic velocity studies in aqueous and aqueous aprotic

solvents mixtures.

CONCLUSION

In the present study, the ultrasonic velocity, density, viscosity and internal

pressure increases whereas adiabatic compressibility, free length and free volume

decreases with increasing concentration of Cetyl Trimethyl Ammonium Bromide in

aqueous and aqueous – aprotic solvent (Dioxane and Tetrahydrofuran) mixtures.

Ultrasonic velocity of THF is slightly higher than dioxane for all aqueous and

aqueous – aprotic solvent (Dioxane and Tetrahydrofuran) mixtures because of due to

their difference in dipole moment.

The CMC values are obtained in aqueous and aqueous – aprotic solvent

(Dioxane and Tetrahydrofuran) mixtures of various compositions of concentration of

Cetyl Trimethyl Ammonium Bromide solutions. The higher CMC values in aqueous

– dioxane mixtures for various composition compared to aqueous – tetrahydrofuran

mixtures of various composition of concentration of Cetyl Trimethyl Ammonium

Bromide. This is due to the average dielectric constant modification in aqueous –

aprotic solvent (Dioxane and Tetrahydrofuran) mixtures of Cetyl Trimethyl

Ammonium Bromide.

315

0.000 0.001 0.002 0.003 0.004 0.005

1495

1500

1505

1510

1515

1520

1525

1530

1535

1540(c

)m s

-2

(X) mol dm-3

Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB

0.000 0.001 0.002 0.003 0.004 0.005

1495

1500

1505

1510

1515

1520

1525

1530

1535

1540

1545

1550

(c)m

s-2

(X) mol dm-3

Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB

0.000 0.001 0.002 0.003 0.004 0.0054.124.144.164.184.204.224.244.264.284.304.324.344.364.384.404.424.444.464.484.50

() x

10-1

0 m2 N

-1

(X) mol dm-3

Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB

0.000 0.001 0.002 0.003 0.004 0.005

0.406

0.408

0.410

0.412

0.414

0.416

0.418

0.420

0.422

0.424

(Lf)

x 10

-10 m

(X) mol dm-3

Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB

0.000 0.001 0.002 0.003 0.004 0.005

0.400

0.405

0.410

0.415

0.420

0.425

(Lf)

x 10

-10 m

(X) mol dm-3

Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB

0.000 0.001 0.002 0.003 0.004 0.005

4.00

4.05

4.10

4.15

4.20

4.25

4.30

4.35

4.40

4.45

4.50

() x

10-1

0 m2 N

-1

(X) mol dm-3

Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB

316

References

1) P.G.T. Fogg, J. Chem. Soc., 83, 117 (1958).

2) J. Millar and A.J. Parker J. Am. Chem. Soc., 83, 117 (1961).

3) D.S. Allam and W. N. Lee, J. Chem. Soc., 6049 (1964).

4) S. Nakamura and S. Meiboom, J. Chem. Soc., 89, 1765 (1967).

5) K. Ramabrahaman, Ind.J.Pure.Appl.Phys.6,75 (1968)

6) C.V. Chaturvedi and S. Prakash, Ind. J.Chem.,10,669(1972)

7) Girish Kumar, Mohinder S Chauhan, Akshat Kumar, Suvercha Chauhan

and Rajesh

Kumar Der Chemica Sinica, 3, 628-635 (2012).

8) Lavinel G.Ionescu, Tadashi Tokuhiro, Benjamin J. Czerniawski, Eric S.

Smith,

Solution Chemistry of Surfactants, 487-496 (1979).

0.000 0.001 0.002 0.003 0.004 0.0051.051.101.151.201.251.301.351.401.451.501.551.601.651.701.751.801.851.901.952.00

(Vf) x

10-6

m

(X) mol dm-3

Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB

0.000 0.001 0.002 0.003 0.004 0.0051.151.201.251.301.351.401.451.501.551.601.651.701.751.801.851.901.952.00

(Vf)

x 10

-6 m

(X) mol dm-3

Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB

0.000 0.001 0.002 0.003 0.004 0.0050.660.680.700.720.740.760.780.800.820.840.860.880.900.920.940.960.981.001.021.041.06

()

x 10

3 pas

cal

(X) mol dm-3

Water+CTAB water+5% THF+CTAB water+10% THF+CTAB water+15% THF+CTAB water+20% THF+CTAB

0.000 0.001 0.002 0.003 0.004 0.0050.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

()

x 10

3 pas

cal

(X) mol dm-3

Water+CTAB water+5% DN+CTAB water+10% DN+CTAB water+15% DN+CTAB water+20% DN+CTAB

317

SYNTHESIS, GROWTH AND CHARACTERIZATION OF

Cd2+ DOPED ZTS CRYSTALS

J.Rajeswari

Department of Physics, Shanmuga Industries Arts and Science College , Tiruvannamalai

ABSTRACT

This article deals with Growth and characterization of doped ZTS crystals, we

have grown cadmium ion doped ZTS crystals by slow evaporation solution growth

technique. To know its suitability for device fabrication, different characterization

analyses have been performed. By powder X-ray diffraction (PXRD) method the it is

found that it exhibits crystalline nature. The thermal stability of the crystal was

examined by TG/DTA analysis and it is observed that the crystal is thermally stable

up to 232° C. Its relative second harmonic generation efficiency was evaluated from

Kurtz powder technique.The mechanical property of the crystal was tested by

Vicker’s microhardness tester.

Key words : Crystal growth , FTIR , TG/DTA, SHG, Micro hardness

1. Introduction:

Nonlinear optics (NLO) is a field of science and technology, which finds wide

applications in the field of telecommunication, optical information and optical

storage devices etc. [1-3]. Recent advances in organic Nonlinear Optical (NLO)

materials have involved a large revival of interest on account of their widespread

potential importance such as their high nonlinearity, high flexibility in terms of

molecular structure, high optical damage threshold [4, 5]. The origin of nonlinearity

in NLO material like thiourea arises due to the presence of delocalized Π electrons

system, connecting donor and acceptor groups and responsible for enhancing their

asymmetric polarizability [6].

Zn(CS(NH2)2)3SO4 is a good engineering material for device applications and

one of the semiorganic nonlinear optical materials (NLO) for second harmonic

generation (SHG) [7,8].ZTS is an important metal-organic crystal. It is used for

electro-optical applications and frequency doubling of near IR laser radiations [9].

In this present study, we examined the effect of doping of cadmium ion with

ZTS on its optical, mechanical and thermal properties.

318

2. Experimental:

Thiourea and zinc sulphate heptahydrate (AR grade) were taken in the ratio

1:3 and dissolved in Millipore water of 18.1 MΩ-cm. The solution was thoroughly

mixed using a magnetic stirrer. It was left for slow evaporation .A crystalline

substance was formed. This synthesized substance was purified by repeated

crystallization process.

A saturated solution was prepared using the recrystallized salt and Millipore

water at room temperature with continuous stirring. The solution was then filtered

using Wattmann filter paper. The filtered solution was poured in to petri dishes and

covered with perforated sheet. It was left undisturbed for slow evaporation. Good

quality ZTS crystals were obtained within 20 days. It is shown in Fig.1.

To grow Cd2+ doped ZTS crystals , 1.1M of cadmium sulphate was added to

the saturated solution of ZTS and stirred continuously to obtain the the homogenous

solution. The solution was then filtered and left for slow evaporation. Crystals with

average size of 8 x 4 x 3 mm3 were obtained after 22 days. As grown Cd2+ doped

ZTS crystals were shown in Fig.2.

Figure.1 Pure ZTS Crystals Figure.2 Cd2+ doped ZTS crystals

3. Characterization techniques:

Fourier transform infrared (FT-IR) spectra were recorded for cadmium doped

ZTS specimens using Perkin Elmer Spectrum RXI spectrophotometer by KBr pellet

technique. Powder X-ray diffraction analysis was also carried out for the grown

crystals in order to understand the crystalline nature of the material using an X-ray

diffractometer. Finely the grounded powder samples were subjected to powder X-ray

319

diffraction analysis using Brucker D8 advance model instrument. The sample was

scanned over the range 10-60° at the rate of 0.02° /minute. To study the thermal

stability of the compound the simultaneous thermo gravimetric analysis (TGA) and

differential thermal analysis (DTA) curves for grown crystals were obtained using a

Seiko TG/DTA 6200 model analyzer in nitrogen atmosphere. The second harmonic

generation test was performed by the Kurtz and Perry powder technique. Adopting

Vicker’s microhardness tester , the mechanical stability of the crystal was tested.

4. Result and Discussion:

4.1 FTIR studies:

The FTIR spectrum of doped crystals is shown in Fig.3. These spectra show a

broad envelope lying in between 2845 cm-1 and 3990 cm-1 and this corresponds to

the symmetric and asymmetric stretching modes of NH2 grouping zinc coordinated

thiourea. The NH2 bending vibration is observed at 1623 cm-1 (10). The C=S

asymmetric stretching vibration is observed the band 715 cm-1. The absorption at

1505 cm-1 is arising out of N-C-N stretching vibration. The band at 461 cm-1 is due

to asymmetric N-C-N bonding. The presence of sulphate ion is confirmed by the

absorption band at 620 cm-1 and 1109 cm-1(10). The presence of additional peak 992

cm-1 in the lower frequency region may be due to the presence of Cadmium in the

coordination sphere.

4.2 Powder XRD studies:

The X-ray diffraction pattern of doped ZTS crystal was shown in Fig.4.The

sharp peaks in the XRD patterns confirm the crystalline nature of the grown

materials. The shift in the peaks of XRD pattern of doped ZTS indicates the

incorporation of cadmium ion in ZTS crystals [11].

4.3 NLO study:

The fundamental Q switched Nd: YAG laser beam of wavelength 1064 nm

with 8 ns pulse width and repetition rate of 10 Hz was used as source. The sample

crystals were powdered and tightly packed between glass slides. The beam was

directed on the powdered sample. The input laser energy incident on the capillary

tube was chosen as 6 J. The second harmonic generation was confirmed by the

emission of green radiation. The second harmonic signal of 202 mV was obtained

320

for Cd2+ doped ZTS crystals, which is 190 mV for pure ZTS. There is slight increase

in the efficiency of ZTS crystals due to doping

4.4 Microhardness studies :

The micro hardness is measured as the ratio of applied load to the surface area

of the indentation. The indentations were carried out using Vicker's indenter for

varying loads. For each load, two indentations were made and the average value of

the diagonal length (d) was used to calculate the micro hardness.

A plot drawn between the hardness value and corresponding loads for

cadmium doped ZTS crystal is shown in Fig. 5. The hardness number was found to

increase with the load. The increase in hardness number of the doped crystal is due

to the strong bond formed between the sulphur and cadmium ions (12).

4.5 Thermal studies. :

The thermogram and differential thermogram of Cd2+ doped ZTS are shown

in Figure 6. From the TGA curve it is inferred that the sample does not have any

water molecules as there is no weight loss around 100° C [13]. The sharp

endothermic peak at 232.1° C is assigned to the melting point of the crystal. The

sharpness of this peak shows the high degree of crystalline nature and purity of the

sample. The crystal has thermal stability of 232.1° C. The second endothermic peak

at 357.5 ° C corresponds to the decomposition of cadmium which also shows the

evidence for the inclusion of cadmium. Above this temperature, zinc starts to melt

and then at 816.9 ° C all the

residues melt.

Fig.3. FTIR spectrum of Cd ions doped ZTS crystal

321

Fig.4. Powder XRD pattern of Cd2+ doped ZTS crystals

Fig.5..LogPVsHv for grown crystal Fig.6. TG/DTA of the sample

5. Conclusion:

The single crystals of ZTS and cadmium doped ZTS were grown by slow

evaporation technique. The crystalline nature of the samples was confirmed powder

X-ray diffraction analysis. FTIR studies identify the functional groups present in the

compound. The SHG analysis reveals that the doping of cadmium increases the

efficiency of ZTS crystal. The hardness study shows the increasing nature of

hardness number with the increase in load. From the thermal studies, it is inferred

20 30 40 50 60 70 80 90 100 11060

70

80

90

100

110

120

Microhardness of Cd2+ doped ZTS

Hv

Load in g

Temp Cel900.0800.0700.0600.0500.0400.0300.0200.0100.0

TG %

104.0

102.0

100.0

98.0

96.0

94.0

92.0

90.0D

TA u

V

15.00

10.00

5.00

0.00

-5.00

-10.00

-15.00

-20.00

3.2%

1.0%

232.1Cel-17.55uV

816.8Cel3.27uV

322

that the doped crystals were thermally stable up to 232.1° C and the doping does not

alter the thermal property of pure ZTS crystals.

References:

1. G. Penn Benjamin, H. Beatriz, Cardelino,Moore Craig E., W. Shields Angels,

D.O.Frazier, (1991). Prog. Cryst. Growth Charact. 22:19.

2. V. Venkataramanan, G. Dhanaraj, H.L. Bhat.,(1994). J. Crystal Growth 140:336.

3. C. Krishnan, P. Selvarajan, T.H. Freeda.,(2008). J. Crystal Growth 311:141.

4. V. Bisder-Leib, M.F. Doherty., (2003). Cryst.Growth Des. 3:221.

5. I. Lediux, J.Badan, J. Zyss. A migus D.Hulin,J.Etchepare, G. Grillon and A.

Antonetti.,(1987) . J.Opt.Soc.Am. B4 (6):987.

6. P.Selvarajan, J.Glorium Arul Raj, S. Perumal.,(2009). J. Crystal Growth

311:3835.

7. S.P. Meenakshisundaram, S. Parthiban, R. Kalavathy, G. Madhurambal,

G. Bhagavannarayana, S.C. Mojumdar, J. Therm. Anal. Calorim. 100 (2010) 831–

837.

8. C. Krishnan, P. Selvarajan, T.H. Freeda, C.K. Mahadevan, Physica B 404 (2009)

289–294.

9. S.S. Gupta, C.F. Desai, Cryst. Res. Technol. 34 (1999) 1329–1332.

10. Rajasekaran R., Mohan Kumar R., Jayavel R. and Ramasamy P. (2003), J.

Crystal Growth, Vol. 252, pp. 317-327.

11. Anand G, Gunasekaran S, Kumaresan S and Kalainathan S , Adv. Appl. Sci.

Res., 2011, 2 (3):550-557.

12. Boomadevi S., Mittal H.P. and Dhanasekaran R. (2004),J. Crystal Growth, Vol.

261 pp. 5562.

13. Gopinath S, Barathan S, Rajasekaran R , J Therm Anal Calorim (2012)

109:841–845.

323

THERMAL AND ACOUSTICAL STUDIES ON SOME

LIQUID ALKALI METALS *P. RAMADOSS, 1V. K. BHAVANISATHIYA

*Asst. Professor, P.G. and Research Department of physics, Govt. Arts College,

Tiruvannamalai-606 603. 1Asst. Professor, P.G. and Research Department of physics,

Shanmuga Industries Arts & Science College,

Tiruvannamalai-606 601.

ABSTRACT

Measurements of sound velocity in solids give useful information regarding

Strength, structure and interaction. In present study using elastic constant

at room temperature has been used to calculate sound velocity at various

direction there by Debye temperature. Mean sound velocity at liquid state has also

been calculated and strength of interaction for Ni, Fe, Ag, Cu, K, Na, Zn and Cd

is study. Heat of fusion, thermal Conductivity have been calculated for above

liquid metals. The results are analyzed.

INTRODUCTION:

Solids are characterized by greater binding forces between atoms than liquid

and gaseous. Using measured ultrasonic velocity in solids, electron-phonon,

phonon-phonon interaction, thermoelastic relaxation, lattice imperfections, grain

boundary losses are explained(1-3). Sound Velocity measurement in solid, liquid

mixtures and solution has been Used with allied parameters to calculate the bulk

properties of the medium (4-5). In solids,sound velocity is effectively used to get

some useful parameters which are not easily got from other means. They are Debye

temperature specific heat, lattice energy etc., at any state of physical condition

(6-8).Thermodynamic properties of liquid metals are calculated using varies

methods(9-10). The properties are entropy, specific heat, isothermal compressibility,

internal energy Helmholtz free energy ect., (11-12) Using these properties

electron-phonon and phonon-phonon interaction, transport properties, diffusion Co-

324

efficient are discussed. In the present investigation the following liquid metals have

been chosen for the study. They are Ni, Fe, K, Ag, Na, Zn, Cu and Cd.

THEORY AND CALCULATIONS:

Debye temperature is the only parameters which describes the properties

remarkably well(16), So it is useful to find as

θD = h/kB [9N/4πv(1/C13 + 2/Cs3)] 1/3

h = Planck’s constant (JS)

KB = Boltzmann constant (JK-1)

N = Avagataro number (mol-1)

V = Molar volume (X 103 mol)

Cl = longitudinal velocity (m/s)

Cs = shear velocity (m/s) and specific heat is related with θD as follows

Cv = (12/5) π4R (T/θD)3J/mol

R = Gas Constant (JK-1 mol-1)

T = Temperature (k)

Cv = Specific Heat Capacity (J/K mol)

The heat of fusion be calculated using the relaxation times at melting

temperature and given temperature as (14)

τm = τTeH/KT

τm&τT = Relaxation time at melting & room temperature (s)

T = Temperature (k)

H = Heat of fusion (KJ/mol)

K = Boltzsmann constant (JK-1)

325

In sound velocity in solid can be calculated using elastic constant an (10)

Cl = √﴾C11/ρ﴿

Cs = √﴾C44/ρ﴿

Where,

ClCs = Longitudinl and shear velocity (m/s)

C11,C44 = Elastic constant X 1010(N/m2)

ρ = density (kg/m3)

In expansion of coefficient in liquid can be calculated using Elastic constant.

KB θ 3 4 πv

-------- X ------- = Um

h 9N

Where,

KB = Boltz’smann constant (Jk-1)

θD = Debye temperature (k)

h = Planck’s constant (Js)

N = Avagodaros number (mol-1)

V = Molar volume (x103 mol)

V – V0

∆V = -------------

V0

∆V = Free volume (m3/mol)

326

V = Molar volume (x103 mol)

Vo = Melting volume (k)

3∆V 1/3

R = ------

4πN

V = Free volume (m3/mol)

N = Avagodaros number (mol-1)

R = Radius (A0)

TABLE: 1

Elastic constant, density, boiling temperature, and acoustical parameters of

Nickel, Iron, silver, sodium, copper, potassium, zinc and cadimum.

Symbols and their meaning used in table: 2

C11 & C44 = Elastic constant (1x 1010N/m2)

ρ = Density (kg/m3)

α = Expansion of coefficient (x10-6k)

TABLE: 2

Mechanical, thermal and acoustical parameters of Nickel, Iron, Silver,

Sodium, Copper, Potassium, Zinc and Cadmium.

Symbols and their meaning used in Table 2;

C11 & C44 = Elastic constant (1X1010N/m2)

ρ = Density (kg/m3)

C1&Cs&Cm = Longitudinal, shear and mean sound velocities (m/s)

327

θDR & θDM = Debye temperature at room temperature and melting Temperature (k)

H = Heat of fusion (KJ/mol)

ρT = Melting temperature (k)

V = Molar volume (kg)

Um = Melting at temperature (k)

C = Ratio between mean sound velocities and melting at

Um = Temperature (m/s)/K

ΔV = Free volume (m3/mol)

RA0 = Radius (A0)

Result and Discussion:

Table 1, gives a elastic constant C11 and C44, density, Co-efficient of thermal

expansion and Boiling temperature. For Ni, Fe, Ag, Cu, K, Na, Zn, and cd(15).

Table: 2, gives calculated Values at Normal and liquid temperature. They are

sound Velocity, Debye temperature, density, Molar Volume, change of Molar

volume, Lattice energy, Radius of empty space.

The sound velocity at normal temperature is greater than boiling

temperature, and Debye temperature at normal temperature is greater than at liquid

state. The ratio between mean sound velocity at normal and mean sound velocity

boiling at temperature is greater than the density higher than the liquid state

interaction between the atoms (i.e),Cadmium(Cd) in normal state is as highest

strength of the interaction at normal then liquid and sodium(Na), as lowest strength

of interaction at normal this reflects ΔV, excess volume, Radius of empty space.

Using Debye relaxation time, heat of fusion been calculated. The calculated

values agree with literature value.

328

TABLE-2 ACOUSTICAL AND THERMAL PROPERTIES OF SOME

ALKALI LIQUID METALS

Syst

em

Cl Cs Cm θD θ*DM Hf ρT V Um Cm/Um ΔV RA

0

Ni 53963 3832.1 4152 557.5 192.5 15.4

(17.8)

7810 7.517 1499 2.769 0.9704 0.7274

Fe 5561.3 3938.1 4269 558.3 299.14 9.37

(13.81)

6980 8.001 2379 1.7941 0.8955 0.7081

Ag 3431.5 2092.3 2310 267.26 103.17 9.76

(11.28)

9320 6.818 778 2.969 1.3760 0.8168

Cu 4335.2 2900.8 3169 414.2 164.99 10.37

(13.26)

8020 7.925 1308 2.422 0.8304 0.6905

K 2312.7

5

1738.7 4621 131.36 97.4 8.47

(2.33)

0.82

8

47.39

3

1401 2.870 1.925 0.9144

Na 2760.6 2080.8 2282 195.3 149.60 0.83

(2.60)

0927 24.80

0

1735 1.315 1.130 0.7652

Zn 4790.2 2332.1 2620 314.5 291.30 0.44

(7.32)

657 9.949 2491 1.0317 0.786 0.6780

Cd 3628.6 1523.2 7996 300.0 184.75 1.31

(6.21)

7996 14.05

7

1773 4.509 1.067 0.7496

Conclusion:

Heat of fusion, Debye temperature at liquid state, Mean sound velocity liquid

state have been calculated theoretically for Ni, Fe, Ag, Cu, K, Na, Zn, and Cd.

329

REFERENCES:

1. W.P Mason, piezoelectric crystals and their application to ultra sound, D.

VanNortrand and Co., Privator (1950),479.

2. W.P Mason physical acoustics Vol III B academic press. Inc..Newyork(1965)

237.

3. W.P Mason & T.B Bateman T.B.J Acoustics Soc., am 40 (1966) 852.

4. Richaards W.T and Reid J.A. Chem. Phys.,1 (1933) 144.

5. Rama Rao, Current science,23 (1954) 325.

6. Reddy T.S and Rao N. Acoustica,61 (1989) 225.

7. Mason W.P & Bateman T.B.J. Acoust. Soc. Am. 6(1964) 645.

8. Reddy R.R. etal Ind J.pure Ultrason, 19 (1997)113.

9. Wei- Qiang Han and Alex Zettl., Appl.Phys. Lett. 80 (2002).

10. Pandey D.K. Singh D and Yadav R.R. Appl. Acoustics 68 (2007) 766.

11. Pandey P.K. Yadawa P.K. Yadav R.R. Materials letters 61 (2007) 5194.

12. J. Blitz, Fundamentals of ultrasonic, Butler worth’s, 1967 London 150.

13. Mason W. P. Physical Acoustics. Vol-II(B) Academic press 1965 (Newyork)

1965.

14. Frenkel J. Kinetic theory of Liquids, Dover Publication.Newyork (1755).

15. G.W.C. Kaye S.T.H. Laboy Tablas & Physical chemical constants 13th ED

Longmans Londan (1968).

16. Durai & Ramadoss P. Bullekin of pure Appl. Science 22(D)(2003) 145.

330

HYDROTHERMAL SYNTHESIS OF CERIUM OXIDE NANO PARTICLES

P.Vijayashanthi1, A.Aarthi1, S. Shanmuga Sundari1*

1Department of Physics, PSGR Krishnammal College for Women, Coimbatore, India.

Corresponding author mail id : shanmugi.s@gmail.com

ABSTRACT

Nano particles have attracted much attention due to the physical and chemical

properties that are significantly different from those of bulk materials. Cerium oxide

is the most abundant element in rare earth family. In the present work Cerium oxide

(ceria) nano particles were prepared by hydrothermal method. Cerium nitrate hexa

hydrate is taken as starting materials and Ammonia as a precipitation agent. Citric

acid is used as size controlling agent. The additives have a strong effect on the

particle size and particle size distribution. Cerium nitrate was dissolved in Distilled

water. And citric acid was added. At the beginning of reaction, The transparent

yellow color came out in the solution subsequently it turned into dark brown color .

The time required for completing the reaction was 8 hrs. The solution was

transferred into Teflon autoclave set up and maintained at 430 K for 24 hrs and then

centrifuged. Finally, centrifuged particles are dried at 353 K. The prepared CeO2

nano particles structure has been analyzed for structural, surface and optical

characteristics. Structure of the prepared particles was examined by XRD and FTIR.

The surface morphology and optical characteristics was studied using SEM, UV and

PL respectively.

Keyword: ceria, hydrothermal, UV, PL, XRD

1. INTRODUCTION

Cerium oxide (CeO2) is a major compound in the useful rare earth family and

has been applied practically in glass-polishing materials, sunscreens, solid

electrolytes and filters, buffer layers with silicon wafer, gas sensors, catalysts in the

fuel cell technology, catalytic wet oxidation, engine exhaust catalysts, NO removal,

photocatalytic oxidation of water and as an ultraviolet absorbent and automotive

exhaust promoter [1-5]. In recent years, ultrafine nanometer-sized particles attracted

much attention due to their physical and chemical properties, which are significantly

331

different from those of bulk materials. Fine particles of cerium oxide with a very

small size have the potential of becoming a very useful material as a fine UV

absorbent and high-activity catalyst [6, 7]. Numerous techniques have been proposed

to synthesize nano-sized CeO2 particles with promising control of properties, such as

hydrothermal, reverse micelles, sonochemical, pyrolysis and homogeneous

precipitation [8,9]. In the present work ceria nanoparticles were prepared by

hydrothermal method.

2. EXPERIMENTAL TECHNIQUE

In the present work ceria nanoparticles are prepared by hydrothermal

method. Cerium nitrate hexahydrate was taken as a precursor, ammonia as a

precipitating agent and citric acid as a size controlling agent. In the room

temperature, Cerium nitrate hexahydrate and citric acid was dissolved in distilled

water and 15 ml of ammonia was added the solution. Suddenly a white precipitate

occurs and as time passed it turns to violet and at the end of the reaction the solution

turns to dark brown color. The brown colored solution shows the Brownian motion

under Green laser. In the whole process the rpm rate was fixed to 850 rpm. The final

solution was transferred to Teflon coated autoclave and heated to 550 K for 12

hours. After that the solution was centrifuged for 45 min using water and ethanol

alternatively. Centrifuged particles were dried at 350 K for 5 hrs, particles are brown

in color. Prepared Ceria particles are characterized by XRD and FTIR for structural

and Optical studies using PL and UV-Vis spectrographs. Surface morphology was

investigated by SEM.

3. RESULTS AND DISCUSSION

3.1.Structural Analysis

3.1.1. X- ray diffraction analysis

Figure 1. XRD pattern of CeO2 nanoparticle

332

XRD pattern was recorded at room temperature from 10o to 80o, 2θ range and

it is shown in figure 1. The high intensity peaks were observed at 28.51, 33.08,

47.44, 56.32, 76.63 respective to the (111), (200), (220), (311), (331) crystal planes.

The crystal planes were in well accordance with JCPDS No: 34-0394 of CeO2

crystal. The diffraction peaks in these XRD spectra indicates the pure cubic fluorite

structure. The average particle size (D) is calculated using scherrer formula,

Ʈ = k /β cos θ (1)

where, τ is mean size of the ordered (crystalline), K is the shape factor, λ is the X-ray

wavelength, β is the line broadening at half the maximum intensity (FWHM) in

radians and θ is the Bragg angle. The crystallite size was found to be in the range

from 7.9-8.6 nm. The value of lattice parameter a calculated from the XRD pattern

and it is found to be 5.4192 Å

3.1.2. Fourier transforms infra-red spectra

Figure 2. FTIR spectrum of CeO2 nanoparticle

The spectrum was recorded in the wave number range of 400-4000 cm-1 at room

temperature as shown in figure 2. The broad absorption band located around 3447

cm-1 corresponds to the O-H stretching vibration of residual water and hydroxyl

groups, while the absorption band at 1620 cm-1 is due to the scissor bending mode of

333

associated water. The band at 703 cm-1 corresponds to bending mode of (C=O) in an

oxalate group. The band position and assignments are given in table 1.

Table 1. Peak assignments of FTIR spectra of ceria nano particles.

WAVE NUMBER (cm-1) BAND ASSIGNMENTS

3521 O-H stretching

3447 O-H stretching vibration of residual water

3386 Bending O-H in water

2884 C-H bonds of the organic compounds

1620 Scissor bending vibration of O-H in water

1529 Vibrations of carbonate group

1374 Vibrations of NO3-1ions

1216 vibration modes ofSO42-

703 Bending mode of C=O in an oxalate group.

510 Stretching vibration

3.2. Surface Analysis – Scanning Electron Micrograph

Figure 3. SEM image of CeO2 nanoparticle

334

Surface and morphological characterization of cerium oxide nanoparticles were

carried out using scanning electron microscopy. Nanosized spherical shaped

CeO2 particles obtained was confirmed. The mean size of the particles was found to

be 10 nm. SEM of cerium oxide nanoparticles is shown in Figure 3.

3.3. Optical Characterization

3.3.1. UV-Vis spectral Analysis

Figure 4. UV spectrum of CeO2 nanoparticle

335

Figure 5. Direct bandgap graph of CeO2 nanoparticle

The UV–visible absorption spectra was recorded from 200 nm to 1200 nm of the

CeO2 and is shown Figure 4. The sample shows a strong absorption below 400 nm

with a well-defined absorbance peak at around 222. In the visible range the sample is

don’t have any absorption. The direct band gap can be determined by fitting the

absorption data to the direct transition equation (2), by extrapolating of the linear

portions of the curves to absorption equal to zero.

αhν = ED (hν − Eg)1/2 (2)

where α is the optical absorption coefficient, hv is the photon energy, Eg is the direct

band gap, and ED is a constant .The estimated band gap of the CeO2 sample is 2.74

eV. The corresponding results are shown in figure 5.

3.3.2. Photo Luminescence analysis

Figure 6. PL spectrum of CeO2 nanoparticle

The PL (figure 6) of the CeO2 mainly consists of four emission bands : a strong

broad emission band at ~ 406 nm (3.06 eV), a strong blue band at 420 nm (2.95eV),

blue gand at ~483 nm, (2.57 eV), and a weak green band at 530 nm (2.34 eV).

336

4. CONCLUSION

Cerium oxide nano particles were prepared by hydrothermal method. The average

particle size (7 nm) were calculated from XRD and SEM and they are in

accordance with each other. The absence of impurity peaks in XRD confirms the

pure formation of ceria. Optical bandgap was calculated from UV-Vis spectra.

REFERENCES

[1] Lunxiang Yin, Yanqin Wang, Guangsheng Pang, Yuri Koltypin, and Aharon

Gedan ken, Sonochemical Synthesis of Cerium Oxide Nanoparticles—Effect of

Additives and Quantum Size Effect, Journal of Colloid and Interface Science

246, 78–84 (2002).

[2] T. Masui, H. Hirai, N. Imanaka, G. Adachi, Synthesis of cerium oxide

nanoparticles by hydrothermal crystallization with citric acid, Journal of

Materials Science Letters 21, 2002, 489– 491

[3] Huey-Ing Chen, Hung-Yi Chang, Synthesis of nanocrystalline cerium oxide

particles by the precipitation method, Ceramics International 31 (2005) 795–802

[4] Huey-Ing Chen, Hung-Yi Chang, Synthesis and characterization of

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