Monte Carlo simulations of small-angle elastic scattering events

Quantitative interpretation of electron spectroscopy is almost always dependent on the understanding of multiple scattering effects. Monte Carlo simulations are often used to model multiple scattering effects, as this method provides for a conceptually simple framework for incorporating both elastic and inelastic scattering processes. In this paper, we demonstrate that when small-angle deflections are important, diffraction effects become significant, and straightforward Monte Carlo simulations are not expected to be valid. However, a simple modification to the Monte Carlo procedure is presented that uses cluster-derived elastic scattering cross sections rather than those derived from isolated atoms. In this way we can incorporate diffraction effects in the simulations. Results from electron momentum spectroscopy are presented to illustrate these effects. These modified simulations greatly improve the agreement between experiment and theory, and this approach builds a bridge between Monte Carlo and diffraction-based interpretations of experiments.