Experimental and theoretical CO2-Ar pressure-broadening cross sections andtheir temperature dependence

Line broadening coefficients of the CO2-Ar fundamental nu (3) band are obta ined experimentally and theoretically for temperatures from 120 to 765 K. T he experimental results are obtained by Fourier-transform infrared spectros copy. Theoretical values are provided via quantum-mechanical (close couplin g and coupled states) approaches as well as semiclassical (improved Smith-G iraud-Cooper and Robert Bonamy) methods. The most up-to-date CO2-Ar ab init io intermolecular potential (J. M. Hutson, A. Ernesti, M. M. Law, C. F. Roc he and R. J. Wheatley, J. Chem. Phys., 1996,105, 9130) is employed for all calculations. For all the temperatures probed, theoretical values are found to be in a rather good agreement with experiment. In addition, the Raman Q (j) line broadening coefficients and the application of the random phase ap proximation are presented.