FTIR Spectroscopy of the 4 bands of 14NO3 and 15NO3

(Okayama Univ., Hiroshima City Univ.)R. Fujimori, N. Shimizu, J. Tang,

K. Kawaguchi, T. Ishiwata

Infrared study of NO3

Present study ; first gas-phase spectroscopy of 4

Determination of C0 from K=3 Combination Difference

( selection rule K = ±1 for 4,

combined with other measurements)

Calculation of inertial defect

1 ; inactive2 ; Friedl and Sander(1987)3 ; very weak intensityOnly Matrix isolation observation　（ Beckers, Willner, Jacox. 2009)

Four fundamental bands

Gr.K

K+1

K+2

K+3

4.

3+4.

K=3 CD

1492 1127

Experimental setup

Liq. He Si bolometer

0.006 cm-1 resolution

Effective path length :48-m

Detector part – Silicon BolometerDewar temperature 4.2 K to 1.7 K

Monitoring of NO3 concentration by HeNe laser

Abs

orpt

ion

of

HeN

e La

ser

discharge On

discharge Off

10 % absorption

Absorption spectrum of the NO3 B-X band

HeNe

(3-m path length)

Sander, J. Phys. Chem. (1986)

Observed spectrum of 14NO3 radical

355.8 355.9 356.0 356.1 356.2 356.3 356.4

0.00

0.05

0.10

(13,6)

(14,9)

(15,12)

(16,15)

pP(N,K)

abso

rban

ce

wavenumber (cm- 1)

Analysis4 band 114 lines PP(N,K) K=5 ～ 29

K=3 ground state combination differences

4 (365), 3+4-4 (1127), 3+4 (1492)

4 combination differences

3+4-4 (1127), 3+4 (1492)

K=0 ground state combination differences

3+4 (1492) rQ(N+1,K) and rR(N,K)

pQ(N-1,K) and pP(N,K)

K = 12

365 cm-1 band

4

Combination differences for K=3 and 4

1492 cm-1

3 + 4

1127 cm-1

15

14

13 14

13

Gr K = 3 combination differences

4 combination

differences

3 hot band of 15NO3 was newly observed

Statistical weight in Analysis4 band 114 lines PP(N,K) K=5 ～ 29 Weight = 1 (accuracy 0.001 cm-1)K=3 ground state combination differences 4 (365), 3+4-4 (1127), 3+4 (1492) Weight = 1/34 combination differences 3+4-4 (1127), 3+4 (1492) Weight = 1/2K=0 ground state combination differences 3+4 (1492) Including diode laser data Weight = 1/2

14NO3 and 15NO3 molecular constants(1)

(Ground state) 14NO3 　　　　　　　 15NO3

present previous 　 present B 0.4585445(86) 0.4585485(63)　 0.458613(14) C 　 　 0.2286679(57) [0.2292743] 0.2287127(89) DN ☓105 0.1092(13) 0.1113(12) 0.1090(25) DNK☓105 -0.2073(26) -0.2121(27) -0.2017(65) DK ☓105 0.1072(18) [0.1034] 　 　 0.0995(52) bb -0.01621(20) -0.01649(13) -0.01549(26) cc 0.00079(14) [0.0] [0.00079]

fit=0.0013 cm-1

DKx105(calc) 0.101 0.0977

present previous present 0 365.48776(35) 365.48419(43) 360.20294(59)B 　 0.4592093(41) 0.4592222(60) 0.4592148(90)C 0.2282897(28) 0.2278233(40) 0.2283252(36)DN ☓105 　 0.0924(16) 0.1019(23) 0.0953(44)DNK☓105 -0.1643(41) -0.1953(58) -0.169(13)DK ☓105 0.0801(28) 0.0973(40) 0.0815(97)C 　-0.042984(14) -0.042063(15) 0.035723(23)N☓105 -0.470(21) -0.431(28) -0.48(13)K☓105 0.379(27) 0.382(36) 0.40(13)q4 0.013276(15) 0.013363(22) 0.013360(66)aeff -0.16581(44) -0.17016(36) -0.16606(50)bb -0.015376(36) -0.015766(36)-0.014498(53)cc 0.000761(26) [0.0] 0.000664(33)

(4 state)　　　14NO3 　　　　　　　 　 15NO3 　　　　　　

14NO3 and 15NO3 molecular constants(2)

Inertial defect of planar symmetric top molecule

harmonic frequencies and 3

Jagod and Oka (1990, JMS)

Check of vibrational assignment

v1 v2 v3 v4 obs calc obs-calc

0 0 0 0 0.1967 0.1961 0.0005 0.3% 1 0 0 0 0.1968 0.1961 0.0007 0.4% 0 1 0 0 0.0665 0.0763 -0.0097 13 % 0 0 1 0 0.2436 0.2573 -0.0137 5 % 0 0 0 1 0.3936 0.3910 0.0026 2 0 0 1 0.4222 0.3910 0.0311 0 2 0 0 -0.0639 -0.0436 -0.0204 30%(max) 0 0 2 0 0.2900 0.3184 -0.0284 0 0 0 2 0.5894 0.5859 0.0035 0 0 0 2 0.5916 0.5859 0.0056 1 1 0 0 0.0798 0.0763 0.0035 1 0 1 0 0.2228 0.2573 -0.0345 1 0 0 1 0.4079 0.3910 0.0169 0 1 0 1 0.2619 0.2712 -0.0093 0 0 1 1 0.4278 0.4522 -0.0244

Inertial defect in BF3 (example, data Maki et al. JMS )

obs=Ic-2 Ib

amu Å2

　　　　 Obs. Calc. O-C Gr. 0.206 0.223 -0.017(0001) 0.434 0.437 -0.003(1001) 0.474 0.437 0.037(00031 1.091 0.864 0.227(0011) 　 0.367 0.487 0.120

3 + 4 = 0 (D3h )

1 (1050), 2 (762) 3 (1127), 4 (365)

In this calc, if 3 = 1492, 3 calc = 0.237Disagreement with observed

Inertial Defects (amu Å2) of NO3

1492 band 3 + 4 ≠ 0 not in D3h (Jahn-Tellar effect )

large p34 [splitting in K=1], aa-bb≠0

4

1+4

34

3+4

=Ic - 2Ib

8 %0.7 %8 %21 %24 %

Relative infrared intensity

3+4(1492 band) = 1.00

band 　 Obs. 　 Calc. （ Stanton ） ν4 (365 cm-1) 0.59 0.26

3ν4 (1173) 0.03 0.06

ν1+ν4 (1413) 0.12 0.31

ν3+ν4 (1492) 1.00 1.00

ν3+2ν4(1927) 0.65 　 0.13 　　J. F. Stanton, Molecular Physics, 107.1059 (2009)

Agreement within factor 2 except for ν3+2ν4

Summary

1. Measurement of the 4 band of NO3

Present 365.7871 cm-1

Matrix 365.6 cm-1

Isotope shift (14N - 15N) = 5.5851 cm-1

2. Determination of C0

0.2286321 (67) cm-1 14NO3

0.228674 (11) cm-1 15NO3

3. Calculations of Inertial defect

v1 v2 v3 v4 obs calc obs-calc 0 0 0 0 0.1576 0.1585 -0.0008 0 1 0 0 0.3089 -1.0765 1.3855 0 0 1 0 0.1776 0.1732 0.0044 0 0 0 1 0.2245 0.9196 -0.6951 0 0 0 1 0.3782 0.9196 -0.5414 0 2 0 0 -0.0975 -2.3115 2.2141 0 0 2 0 0.1981 0.1880 0.0102 0 0 0 2 0.5424 1.6808 -1.1384 0 0 0 2 0.5445 1.6808 -1.1363 1 1 0 0 0.3317 -1.0765 1.4082 0 0 1 0 0.1827 0.1732 0.0095 1 0 0 1 0.2041 0.9196 -0.7156 0 1 0 1 0.2216 -0.3153 0.5370 0 0 1 1 0.2544 0.9344 -0.6800 0 0 0 0 0.1576 0.1585 -0.0008 0 0 0 3 0.3679 2.4420 -2.0741 0 1 0 2 0.4369 0.4458 -0.0090 0 2 0 1 0.5243 -1.5503 2.0746 0 1 1 0 0.2999 -1.0618 1.3616

Inertial defect in SO3 (example, data Maki et al. JMS )

obs=Ic-2 Ib

amu Å2