Collision induced light scattering from fluids composed of tetrahedral molecules

Abstract

The collision induced isotropic and anisotropic spectra of light scattered from fluids of tetrahedral molecules are examined. The interaction function used includes the dipole-induced dipole effect (DID) and the collision induced rotational Raman effect (CIRR) to lowest order. The spectra are expressed as the Fourier transforms of four point correlation functions which contain the number density and the orientational density of the particles. The polarization ratio I _VV ^CIRR(ω)/I _VH ^CIRR(ω) for the CIRR contributions considered is shown to be 37/9 for all densities. The various terms contributing to the integrated intensity for the pair and triplet collisions are expressed in terms of the irreducible expansion coefficients of the orientation dependent pair distribution function. As an example, these terms are evaluated numerically for carbon tetrachloride for two different densities corresponding to a liquid and a vapour state.