Infrared spectroscopy of two isomers of the OCS-CS2 complex

J. Norooz Oliaee, M. Dehghany, Mahin Afshari, N. Moazzen-AhmadiDepartment of Physics and Astronomy, University of Calgary

A. R. W. McKellarSteacie Institute for Molecular Sciences, National Research Council of Canada

OutlinePrevious work on OCS-CS2

Our recent work on OCS-CS2

Comparison with similar species OCS-CO2

CO2-CS2

Summary

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FTMW

Observation

OCS-CS2 dimer: Previous Work

ORIENT

Semi-Empirical Modeling

ORIENT

Semi-Empirical Modeling3/11

2057.6 2057.8 2058.0 2058.2

wavenumber/cm-1

Experiment

Simulation

OCS-CS2 dimer: Our recent workInfrared observation of the lowest-energy isomer of OCS-CS2 at ~ 2057.91 cm-1

Structure I

Cs symmetryPlanar

a- and b-type@ ~ 2057.91 cm-1

Blank regions indicate OCS absorption lines. 4/11

2059.4 2059.6 2059.8 2060.0

wavenumber/cm-1

Experiment

Total

OCS-CS2-Crossed

OCS-CS2-parallel

He-OCS

Infrared observation of the intermediate-energy isomer of OCS-CS2 at ~ 2060.07 cm-1

Blank regions indicate OCS absorption lines.

Structure II

Cs symmetryNon-planar

Predominantly c-type@ ~2060.07 cm-1

OCS-CS2 dimer: Our recent work

Sid

e

view

Top

view

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a

c

b

Structure of the intermediate-energy isomer of OCS-CS2

Structure II

Cs symmetryNon-planar

Predominantly c-type@ ~2060.07 cm-1q

RCM

Rotational and Structural Parameters Comparison Table

A/MHz B/MHz C/MHz RCM /Å q/ ° Dihedral/ °

Peebles’ Group* 2138 1029 898 3.490 84.8 90.0

Our Group 2187.7(4.5) 997.8(1.8) 864.13(33) 3.5578(17) 74.89(46) Crossed

* Semi-empirical modelling by ORIENT program

OCS-CS2 dimer: Our recent work

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Comparison with similar species:OCS-CO2 dimer: previous studies

FTMW observation of the planar S-interior slipped near-parallel OCS-CO2 dimer

ab initio calculations for O-interior slipped near-parallel OCS-CO2 dimer

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Comparison with similar species:OCS-CO2 dimer: Our recent studies

Isomer a structural parametersRCM /Å q1/ ° q2 / °

Novick et al*

3.552(3) 68.94(30) 78.93(57)

Our Group 3.5545(10) 69.7(4) 78.7(3)

Isomer b structural parametersRCM /Å q1/ ° q2 / °

Valdes et al†

3.913 122.45 131.05

Our Group

3.9862(10) 118.0(5) 135.8(3)* FTMW observation† ab initio calculations at the MP2/cc-pVTZ level

@ 2066.1 cm-1 @ 2055.7 cm-1

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Comparison with similar species:CO2-CS2 dimer: previous studies

Cross-shaped@ ~ 2346.55 cm-1

withRCM=3.392 (Å)

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Lowest-energy isomer

Intermediate-energy isomer

Highest-energy isomer

OCS-CS2

OCS-CO2

CO2-CS2

Summary

MW1

IR IR

MW2

IR3

IR3

MW4

IR

1 Josh J. Newby et al, Phys. Chem. Chem. Phys. 7, 487-492 (2005)2 Stewart E. Novick et al, J. Chem. Phys. 88, 687 (1988)3 M. Dehghany et al, J. Chem. Phys. 130, 224310 (2009)4 C. C. Dutton et al, J. Phys. Chem. A 102, 6904-6909 (1998)

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Thanks for your attention!