Evaluation of electron inelastic mean free paths for selected elements and compounds

Abstract

We have performed an evaluation of calculated and measured electron inelastic mean free paths (IMFPs) for selected materials and for electron energies between 50 eV and 10 000 eV. This evaluation is based on IMFPs calculated from experimental optical data and on IMFPs measured by elastic-peak electron spectroscopy. The methods used for the calculations and measurements are briefly described, together with the various sources of uncertainty. We have evaluated calculated and measured IMFPs for four elements (Fe, Mo, W and Pt) and calculated IMFPs for six compounds (aluminum oxide, silicon dioxide, potassium chloride, poly(butene-1-sulfone), polyethylene and polystyrene). Good consistency was found among the calculated IMFPs and reasonable consistency was found between the calculated and measured IMFPs. The degree of consistency in each case is similar to that found in a previous evaluation of calculated and measured IMFPs for Al, Si, Ni, Cu, Ge, Ag and Au. Finally, we have compared IMFPs from the predictive IMFP equation TPP-2M with recommended IMFPs for Ni, Cu, Ag and Au obtained from the earlier evaluation. This comparison indicated that the standard uncertainty of IMFPs from the TPP-2M equation, relative to the recommended IMFPs, was 1.0 A or 9.2%. Copyright © 2000 John Wiley & Sons, Ltd.