Theory of Raman scattering on normal metals with impurities

The Raman spectrum is calculated for a simple metal with nonmagnetic impurities in the zero-momentum-transfer limit. The Raman scattering is due to electron-hole excitations. The effect of the impurities is in the fluctuation of the electron distribution between different parts of the Fermi surface, which results in overdamped zero-sound channel modes of different symmetries. Analogous phenomena have already been observed in semiconductors. Comparison with the recent theory of Falkovsky is also made.