Universal quantification of elastic scattering effects in AES and XPS

Elastic scattering of photoelectrons in a solid can be accounted for in the common formalism of XPS by introducing two correction factors, beta(eff) and Q(x). In the case of AES, only one correction factor, Q(A), is required. As recently shown, relatively simple analytical expressions for the correction factors can be derived from the kinetic Boltzmann equation within the so-called ''transport approximation''. The corrections are expressed here in terms of the ratio of the transport mean free path (TRMFP) to the inelastic mean free path (IMFP). Since the available data for the TRMFP are rather limited, it was decided to complete an extensive database of these values. They were calculated in the present work for the same elements and energies as in the IMFP tabulation published by Tanuma et al. An attempt has been made to derive a predictive formula providing the ratios of the TRMFP to the IMFP. Consequently, a very simple and accurate algorithm for calculating the correction factors beta(eff), Q(x) and Q(A) has been developed. This algorithm can easily be generalized to multicomponent solids. The resulting values of the correction factors were found to compare very well with published values resulting from Monte Carlo calculations.