A SELF-CONSISTENT OPTICAL-POTENTIAL THEORY FOR ATOMS IN SOLIDS

We develop an approximation for the optical potential in a solid, vali d at intermediate energies, i.e. energies greater than 50 eV. The pres ent approximation for the optical potential builds on the GW-expressio n. We separate the RPA polarization propagator into a core electron an d a valence electron, and can then achieve a corresponding separation of the optical potential. We apply this method to electron-Ne and -Ar elastic scatterings and find a satisfactory agreement with the observe d results. We also study the importance of self-consistency and the se nsitivity to a parameter, the average excitation energy. (C) 1998 Else vier Science B.V.