Theory of Atomic Optical Potential in Solid Application to Electron-Helium Scattering

Abstract

We develop an approximation for the optical potential in a solid valid at intermediate energies, i.e., above about 50, eV. The present approximation for the optical potential is based on GW-expression. We separate the RPA polarization propagator into a core-electron and a valence-electron part, and can then achieve a corresponding separation of the optical potential. We apply this method to electron-He elastic scattering, and we find satisfactory agreement with the observed results. We also study the importance of self-consistency, and the sensitivity to a parameter, average excitation energy.