TEMPERATURE, PRESSURE, AND PERTURBER DEPENDENCIES OF LINE-MIXING EFFECTS IN CO2 INFRARED-SPECTRA - II - ROTATIONAL ANGULAR-MOMENTUM RELAXATION AND SPECTRAL SHIFT IN SIGMA[-SIGMA BANDS

The Energy Corrected Sudden approach is used in order to deduce collis ional parameters and to model infrared quantities in Sigma-Sigma bands of CO2-He and CO2-Ar mixtures at room temperature. Measurements are f irst used for the determination (from a fit) of the rotational angular momentum relaxation time and of some parameters representative of the imaginary part of the relaxation operator. It is shown that fine-broa dening data as well as absorption in both the wing and central part of the nu(3) and 3 nu(3) bands lead to consistent determinations. The mo del is then used for detailed analysis of line-mixing effects. The inf luences of pressure, of the band spectral structure, and of the collis ion partner are studied. Differences between the effects of collisions with He and Ar are pointed out and explained. (C) 1998 American Insti tute of Physics. [S0021-9606(98)00232-3].