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Herman–Wallis correction in vibrational CARS of oxygen

✍ Scribed by Michele Marrocco

Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
442 KB
Volume
42
Category
Article
ISSN
0377-0486

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✦ Synopsis

Abstract

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.

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