Spectral line-shapes and moment analysis in isotropic and anisotropic light scattering spectra for gaseous argon

Abstract

For direct comparison with the measurements of isotropic and anisotropic collision-induced light scattering spectra of argon gas at room temperature performed by Le Duff's group, quantum mechanical lineshapes are computed using different models of the interatomic potential and models of the diatom polarizability tensor invariants as input. New empirical trace and anisotropy parameters, consistent with the spectroscopic measurements, are thus obtained for the argon gas. These are compared, where possible, with existing computations based on classical physics, utilizing the first few even moments of the isotropic and anisotropic light scattering spectra. Some discrepancies with experiment, specially for the second Kerr coefficient, are found, but overall the agreement is satisfactory and the profiles calculated with these models coincide with experiments.