Light scattering from disordered media

The Raman scattering cross-section in molecular systems is calculated with the aim of accounting for the low frequency spectrum of disordered media. It is shown that, as far as translational motions are concerned, the isotropic polarizability correlation function is not strongly affected by the structural disorder and is essentially determined by the density-density correlation function. In contrast the anisotropic term depends strongly on the disorder of the system. Its contribution to the scattered light spectrum is governed by single molecule dynamics, thus reflecting in some cases the entire density of translational states, while the intensity is determined by the rotational—translational coupling.