DIFFERENTIAL CROSS-SECTIONS FOR PLASMON EXCITATIONS AND REFLECTED ELECTRON-ENERGY-LOSS SPECTRA

Electron differential inverse mean free paths for volume-plasmon excit ations and differential probabilities for surface-plasmon excitations have been calculated using dielectric response theory. A model dielect ric function which satisfied sum rules and agreed with optical data wa s established for these calculations. In surface-plasmon calculations, we considered electron-impact emissions of the reflected electron-ene rgy-loss spectroscopy. Formulations were made for obliquely incident e lectrons with the recoil effect and without the small-scattering-angle assumption. For volume-plasmon excitations, we evaluated corrections due to the exchange and Z1(3) effects. Comparison between calculated r esults and experimental data extracted from reflected electron-energy- loss spectra showed good agreement. Calculated differential cross sect ions have been used to solve the transport equation for the angular an d energy flux spectra of reflected electrons. Contributions to the spe ctra from single and plural plasmon excitations were analyzed. It was found that calculated spectra were in good agreement with measured dat a.