Spectra of molecular light scattering and some of their applications

Certain problems in the theory of the spectra of light scattered by optical inhomogeneities induced by fluctuations of different orgin are discussed. Examples are given of the applications of light-scattering spectroscopy to the study of the propagation of hypersound in various substances and under different conditions, including the region of critical phenomena at phase transitions, the magnon spectra of ferromagnetic and antiferromagnetic materials; the Mandelstam—Brillouin spectra of piezoelectric semiconductors in static electric fields; the phonon bottleneck; the temperature dependence of concentration-fluctuation correlation radius, the Mandelstam—Brillouin spectra in the presence of a steady-state temperature gradient, the fine structure of the Rayleigh line wing, and the propagation of transverse hypersound when the shear viscosity of a medium is varied over a wide range.