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Herman–Wallis correction in vibrational CARS of oxygen
Author(s) -
Marrocco Michele
Publication year - 2011
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2965
Subject(s) - raman spectroscopy , diatomic molecule , raman scattering , rotor (electric) , coupling (piping) , rotation (mathematics) , chemistry , line (geometry) , combustion , gas phase , atomic physics , molecular vibration , oxygen , molecule , phase (matter) , molecular physics , optics , physics , materials science , quantum mechanics , computer science , geometry , mathematics , organic chemistry , artificial intelligence , metallurgy
Light molecules are subject to vibration–rotation (VR) interaction, which implies corrections to the rigid rotor approximation and, in particular, corrections to spectral line intensities are related to the so‐called Herman–Wallis (HW) factor. This problem is outlined here for the spectral response of some medium‐weight diatomics in the gas phase and probed by means of vibrational coherent anti‐Stokes Raman scattering (CARS) used for diagnostic reasons in combustion science. However, different from other works on this subject, we specialized our analysis to oxygen and, since the peculiarity of its anti‐bonding molecular orbital, we find that the VR coupling is responsible for deviations that compete with the effect of Raman line widths typical of collisional environments of hot gases at room pressure. The HW correction is ultimately demonstrated to affect O 2 CARS thermometry in such a manner that the accuracy for measurements at high temperatures can be improved. Copyright © 2011 John Wiley & Sons, Ltd.