Mean excitation energy and electronic stopping power of solids

Abstract

Abstract The mean excitation energy, I, of some solid materials has been studied. An examination for the local-plasma approximation and a discussion about theoretical connections for I between solid and gaseous materials have been made. This examination led to the development of a combined model which utilized the local-plasma approximation for inner-shell electrons and the dielectric response function for valence electrons. In the local-plasma approximation, we have used electron density distribution obtained from the Hartree-Fock model with the Wigner-Seitz boundary condition for solid atoms. A Drude-type dielectric function for multi-group valence electrons was applied to the valence band. From first principles, we have calculated the mean excitation energy as varying with the energy of incident electrons. Applying these data to the Bethe stopping power formula, we were able to extend successfully this formula to lower electron energies.