Oswald-Kasper-Gaukler model for reflection electron energy loss spectroscopy

The Oswald-Kasper-Gaukler (OKG) model for elastic electron backscattering [J. Electr. Spectrosc. Rel. Phen. 61(1993) 251] has been extended within the partial-intensity approach to take inelastic collisions into account. Analytical expressions have been derived for the path-length distribution and the partial intensities, achieving good agreement with results of Monte Carlo (MC) calculations of these quantities. A criterion is given to predict the validity of the model for a given material, geometry, and kinetic energy. Experimental reflection electron energy loss spectroscopy (REELS) spectra have been compared with REELS spectra calculated using the modified OKG model, obtaining good agreement between them. The proposed model is also applied in a quantitative analysis of experimental REELS. In all investigated cases, the single-scattering loss distributions retrieved from this analysis agree with results from previous analyses-based on MC calculations-within 5%. The presented model can therefore be employed in quantitative analyses of REELS of semi-infinite solids, while it is both numerically simpler and conceptually clearer than related approaches.