Brillouin-Streuung an dichten Fluiden

On Brillouin Scattering in Dense Fluids It has been shown analytically that Mountain 's theory of the spectral distribution of density fluctuations in fluids having an external degree of f reedom (MOUXI) is equivalent to the translational hydrodynamics theory (TH) of Desai and Kapral at liquid state densities where selfdiffusion can be neglected. On the other hand, comparing TH and Mountain's second theory of Brillouin scattering on thermal relaxing fluids involving a frequency dependent volume viscosity (MOUETA), differences are found in several spectral components, especially the intensity of the Rayleigh line, of the Brillouin spectra of CC14, C6H1 2 and C 6 H 6 at large values of the wave vector k. This theoretical effect can be demonstrated experimentally by fitting TH and M O U E T A to experimental Brillouin spectra of CC14 at high values of k, resulting in small changes of the corresponding relaxation times.