Isosteric and isothermal studies of the Raman depolarization ratios in an argon-methane mixture at 298 K and 323 K

Abstract

Raman depolarization ratios (RDRs) have been measured for a 10 mole % methane solution in argon at 298 and 323 K over a wide range of densities corresponding to pressures from 49 to 2200 bars. In addition, the anistropic Raman time correlation functions (TCFs) at these conditions have been recorded. The results are in striking contrast to previous work on pure methane and 10% methane in carbon dioxide where there was strong evidence for angular dependency of the intermolecular potential functions. In argon, apparently, the isotropic atomic potential gave rise to little change in either the RDR or the TCF values as might have been expected, but had to be confirmed in order to understand the process involved.