Abstract
The spectral distribution of light scattered by spontaneous density fluctuations in a binary mixture of monatomic ideal gases is studied by using a kinetic model of the Boltzmann equation which is compatible with the two-fluid hydrodynamic theory. Comparison of the theoretical results with available light scattering experiments in helium–xenon gas mixtures shows that the two-fluid model equation can be applied to describe the light scattering spectra at wavenumbers such that species temperature separation produces strong deviations from the classical hydrodynamic predictions.