LINE-SHAPE, TRANSPORT AND RELAXATION PROPERTIES FROM INTERMOLECULAR POTENTIAL-ENERGY SURFACES - THE TEST-CASE OF CO2-AR

Two new potential surfaces for CO2-Ar, obtained principally from the s pectra of van der Waals complexes, are tested against measurements of pressure broadening and of transport and relaxation properties, none o f which was used in the determination of the surfaces. Pressure broade ning of both infrared and Raman lines is considered. The coupled state s (CS) approximation is used for all line shape calculations. Thermall y averaged infrared and Raman cross sections at 523, 296, 160 and 77 K (infrared) and 245 K (Raman) show good agreement with the experimenta l data available. Generalized transport and relaxation cross sections are obtained via full classical trajectory and classical CS calculatio ns. Properties tested include diffusion, viscosity and nuclear spin re laxation. They provide a different test of the surfaces and agree well with experiment. (C) 1997 American Institute of Physics.