1 ab initio and infrared studies of carbon dioxide containing complex zheng su and yunjie xu...
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Ab initio and Infrared Studies of Carbon Dioxide Containing Complex
Zheng Su and Yunjie Xu
Department of Chemistry, University of Alberta,
Edmonton, Alberta, Canada
June, 2005
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Introduction Chirality and chiral interaction
Our approaches Ab initio theoretical investigations High resolution molecular spectroscopy
enantiomers
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Molecules under Investigation
Cyclopropane(C3H6)•CO2
CO2 monomer : asym = 2349 cm-1
Accessible region of our laser: 2336 – 2434 cm-1
Propylene Oxide(PO)•CO2
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Ab initio Calculations for PO•CO2 ‡
2.798
2.760
2.711 2.696
2.774
∆ = -2.8 cm-1
∆ E = -18.91 kJ/molA = 3.987 GHz B = 1.635 GHzC = 1.482 GHz
∆ = -3.3 cm-1
∆ E = -18.21 kJ/molA = 5.363 GHzB = 1.261 GHzC = 1.206 GHz
‡ Gaussian 03, MP2/cc-pVDZ for harmonic frequency calculations; MP2/aug-cc-pVDZ for geometry optimizations.
Å
Å
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Simulated Spectrum of PO•CO2
T=2KQ-branch
Kisiel, Z., Białkowska-Jaworska, E. and Pszczółkowski, L., J. Chem. Phys. 109(23), 10263, 1998.
Frequency /cm-1
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Rapid Scan Mid-IR Diode Laser Spectrometer
L5830 TDL control
L5740TDL Dewar
Off-axis parabolic mirror
Beam splitter
iris
Ref. cellor étalon
L3
D2Amplifier 2
Nozzledriver
nozzle
To pump
L1
L2
D1
Amplifier 1Vacuum chamber
cell
Computer Function generator
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Experimental Setup
Laser source dewarCollimation assemblyReference detection
Signal detection of the molecular complex
Vacuum chamber
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Astigmatic Multi-path Cell Assembly
back front
spot pattern of 182-pass configuration → 37m absorption length
Mirror mount
McManus, J.B., Kebabian, P.L. and Zahniser, M.S., Appl. Opt. 34(18), 3336, 1995.
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Rapid Scan Technique
trigger fornozzle driver
current ramp for laser controller
trigger for data acquisition
Piante, A.D., et al., Rev. Sci. Instrum. 60(5), 858, 1989.
Time /ms
background pulse signal
0 1 2 3 4 5
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Example Spectrum of Ar•CO2 R(0)
R0 8
Q0
Randall, R.W., et al., Faraday Discuss. Chem. Soc., 85, 13, 1988.
R(17)R(37)
R(25)
2349.06 2349.42 2349.78 Frequency /cm-1
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Search for PO•CO2 Complex
Carrier gas:
Ar, Ne, He Nozzle:
0.8mm pinhole,
60m slit PO/CO2 ratio:
1/3, 1/1, 2/1, 5/1,10/1
— 0.5% CO2 in 1.5 bar Ar— 0.5% CO2 5% PO in 1.5 bar Ar
2349.24 2349.78 Frequency /cm-1
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∆ E = -28.57 kJ/mol
Vs.
∆ E = -18.91 kJ/mol
Vs.
∆ E = - 7.24 kJ/mol
Competing Formation of Dimers
PO•PO PO•CO2 CO2•CO2
C3H6
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Rovibrational Spectra of C3H6•CO2
2348.82 2349.06 2349.30 Frequency /cm-1
R(16) R(37)R(25)R(32)
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Comparison of Nozzles
C3H6:CO2 = 3:1100 averaging cycles
2347.20 2347.30 2349.40 2349.50 Frequency /cm-1
R(9)R(22)
R(28)
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Simulated Spectra of C3H6•CO2
∆ E = -8.756 kJ/mol∆ = -2.18 cm-1
Frequency /cm-1
∆ E = -9.329 kJ/mol∆ = -5.08 cm-1
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Comparison between Experimental and Simulated Spectra
2344.2 2345.0
2347.84 2348.08 2348.482348.22
Cal.
Exp.
Frequency /cm-1
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Summary and Future Work
Construction of a rapid scan mid-IR diode laser spectrometer
Measurements of C3H6•CO2 complex
Structural analysis of C3H6•CO2 complex
Investigation of PO•CO2 complex Study of chiral interactions
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Acknowledgement
Dr. Waishun Tam and Dr. Nicole Borho Dr. Wolfgang Jäger and his group Dr. Igor Leonov for programming Roman Lipiecki for the mechanical parts Alberta Ingenuity Fund for a Studentship NSERC Thank you for the attention !!!