Coherent Raman and Infrared Studies of Sulfur Trioxide

Published

December 1, 2001

Author(s)

E T. Chrysostom, N Vulpanovici, Tony Masiello, J Barber, J W. Niblez, A Weber, A G. Maki, Thomas A. Blake

Abstract

High resolution (0.001 cm^-1) coherent anti-Stokes Raman scattering (CARS) was used to observe the Q-branch structure of the IR-inactive Ņ₁ symmetric stretching mode of ³²S ¹⁶0₃ and its various ¹⁸O isotopomers. The Ņ₁ spectrum of ³²S¹⁶0₃ reveals two intense Q-branches In the 1065-1067 cm^-1 region, with surprisingly complex vibrational-rotational structure not resolved in earlier studies. Efforts to simulate this with a simple Fermi-resonance model involving Ņ₁ and 2 Ņ₄ states do not reproduce the spectral detail nor do they yield reasonable spectroscopic parameters. A more subtle combination of Fermi resonance and indirect Coriolis interactions withnearby states; 2 Ņ₄ (I = 0, 2), [nu}₂ + Ņ₄ (I = 1), 2 _Ņ2 (I = 0) is suspected and a determination of the location of these coupled states by high resolution infrared measurements is underway. At medium resolution (0. 125 cm^-1), the infrared spectra reveal Q-branch features from which approximate band origins are estimated for the Ņ₂, Ņ₃, and Ņ₄ fundamental modes of ³²S¹⁸O₃, ³²S¹⁸O₂¹⁶O and ³²S¹⁸O¹⁶O₂. These and literature data for ³²S¹⁶O₃ are used to calculate force constants for SO₃ and a comparison is made with similar values for SO₂ and SO. The frequencies and force constants are in excellent agreement with those obtained by Martin in a recent ab initio calculation .

Citation

Journal of Molecular Spectroscopy

Volume

210

Issue

No. 2

Pub Type

Journals

Keywords

cars, coherent raman, infrared, raman, spectrum, sulfur trioxide

Citation

Chrysostom, E. , Vulpanovici, N. , Masiello, T. , Barber, J. , Niblez, J. , Weber, A. , Maki, A. and Blake, T. (2001), Coherent Raman and Infrared Studies of Sulfur Trioxide, Journal of Molecular Spectroscopy (Accessed December 4, 2024)