Identification of 1, 2 and 3 body Raman scattering by the field gradient induced dipole A tensor in methane

Abstract

In previous work involving the v 1 mode, Raman depolarization ratio (RDR) density dependent studies of supracritical methane, 10% methane in carbon dioxide, and 10% methane in argon, the present authors had hypothesized that the Coriolis coupling and resulting dipole moment played a leading role in the explanation of the RDR versus density (pressure) dependence found. This was necessitated by the fact that we could find no direct evidence for interaction induced ii, i.e., 2-body and 3-body light scattering. That evidence has now been identified from the previously recorded pure methane data and is the subject of this paper. It should be noted, however, that this current interpretation reverses the previous arguments for angular dependent intermolecular coupling as a contributing factor in addition to translational ii in explaining the earlier RDR results.