A molecular dynamics study of depolarized interaction induced light scattering in room temperature argon

Abstract

Precise experimental measurements by Barocchi, F., Carraresi, L., and Celli, M., 1992, Phys. Rev. A, 46, R3598 of the interaction induced scattering line shape in argon gas over a wide density range prompted a molecular dynamics study of the line shape density behaviour. Different polarizability models and intermolecular potentials are tested in the simulations. As the density increases, the spectral shape seems to become less dependent on the polarizability model but the absolute intensity value becomes more dependent on it. The scattering intensity is found to depend strongly on the polarizability model used in the simulation and slightly on the intermolecular potential. The SCF polarizability approach by Dacre, P. D., 1982, Molec. Phys., 45, 1 and the polarizability model of Joslin, C. G., Goddard, J. D., and Goldman, S., 1996, Molec. Phys., 89, 791, which includes correlation effects, are found to reproduce the spectra well at every density. The two- and many-body intensity ratios are shown not to decrease systematically with the frequency shift increase, as was supposed previously. Instead, a frequency shift range is found where the global density effect on the spectral intensity on binary units is weak. The dipole–induced dipole model also is found not to reproduce the low frequency shift spectrum in absolute units when the density is sufficiently high.