Lifetimes of long wavelength longitudinal phonons in impure metals
The standard Green function theory of electron-phonon interaction in metals is extended to include the effect of impurities moving with the lattice. The importance of various diagrams in the perturbation expansion of the phonon Green function is discussed in the light of the accepted theories of ultrasonic absorption in impure metals. The screened impurity potential is treated as arbitrary function of the scattering angle.