RAMAN SCATTERING IN LIQUID HELIUM

A theory of light-scattering processes in liquids in which two excitations are created or annihilated is developed. The basic ideas are similar to those in the Lorentz-Lorenz theory of the propagation of light in material media. The spectrum of scattered light is expressed in terms of an integral over two density-density correlation functions. The angular dependence and polarization of the scattered light is determined. The results are compared with recent light-scattering experiments on He II. © 1969 The American Physical Society.