Line shape, transport and relaxation properties from intermolecular potential energy surfaces: The test case of CO2–Ar

Abstract

Two new potential surfaces for CO2–Ar, obtained principally from the spectra of van der Waals complexes, are tested against measurements of pressure broadening and of transport and relaxation properties, none of which was used in the determination of the surfaces. Pressure broadening of both infrared and Raman lines is considered. The coupled states (CS) approximation is used for all line shape calculations. Thermally averaged infrared and Raman cross sections at 523, 296, 160 and 77 K (infrared) and 295 K (Raman) show good agreement with the experimental data available. Generalized transport and relaxation cross sections are obtained via full classical trajectory and classical CS calculations. Properties tested include diffusion, viscosity and nuclear spin relaxation. They provide a different test of the surfaces and agree well with experiment.