Elastic and Inelastic Diffraction of Low-Energy Electrons from Al (100): Double-Diffraction Model

Abstract

The isotropic-scatterer, inelastic-collision model is used to analyze experimental elastic intensity profiles characteristic of electrons in the energy range 10≤E≤120 eV scattered from Al(100). Using the double-diffraction approximation a satisfactory description of these profiles is achieved for a variety of incident beam angles, θ≤25°. The temperature dependence of these profiles due to both thermal expansion and lattice vibrations is examined. Using the inelastic-collision-model description of the elastic scattering, the RPA plasmon dispersion relations and lifetimes, and the sharp-junction, “uniform” electron fluid electron-plasmon interaction vertices, the inelastic energy and angular profiles for the two-step excitation of bulk and surface plasmons are predicted using a double-diffraction analysis of this process. Observation of these profiles and their correlation with such an analysis constitutes a critical test of existing models of inelastic diffraction.