CARS thermometry revisited in light of the intramolecular perturbation

The rigid rotor approximation (RRA) is commonly assumed in the Raman cross section used in thermometric analysis based on coherent anti-Stokes Raman scattering (CARS). In this paper, we discuss instead the role of the coupling between molecular vibrations and rotations in view of the alterations found in the amplitude of CARS signals of basic molecules and, in the end, we demonstrate that the deviation of a few percent from the RRA results in corrections to the measured temperature that are comparable to the thermometric accuracy of very well-known Q-branch CARSmeasurements on nitrogen, which is unanimously regarded as the fundamental molecule in CARS thermometry. Copyright (C) 2010 John Wiley & Sons, Ltd.