Inelastic Interaction of Medium-Energy Electrons with Ni Surface Studied by Absolute Reflection Electron Energy Loss Spectrum Analysis and Monte Carlo Simulation

Abstract

  The results of the investigation of the inelastic interaction of medium-energy electrons with the Ni surface were described. The inelastic mean free path (IMFP), the surface excitation parameter (SEP) and the differential SEP (DSEP) were deduced simultaneously from an absolute reflection electron energy loss spectroscopy (REELS) spectrum. The present IMFPs show a good agreement with those calculated using the TPP-2M predictive equation. The dependence of the SEPs on the electron energy is similar to that calculated using Werner’s and Gertgely’s predictive equations. The DSEPs show a reasonable agreement with the theoretical DSEPs calculated using Tung’s theory with optical data. The derived IMFP, SEP and DSEP were applied to Monte Carlo simulation of REELS spectra, in which energy loss processes of signal electrons due to surface excitations were taken into account. The simulated REELS spectra reproduce the experimental absolute REELS spectra well without any fitting parameters, indicating that surface excitations play an important role in the inelastic interaction of medium-energy electrons with the solid surface.