Azimuthal scans in LEIS: Influence of the scattering potential

Angular scans were performed for a Cu(1 0 0) single crystal and 3 keV He+ ions. The results were compared to simulations using the Monte-Carlo code TRIC [R. Andrzejewski, Ph.D. thesis, Universidad Autonóma de Madrid, 2008; V.A. Khodyrev, R. Andrzejewski, A. Rivera, D.O. Boerma, J.E. Prieto, in press] to obtain information on the ion–atom interaction. Different potentials were used in the simulations, e.g. the Thomas–Fermi–Moliere potential with a modified screening length and a Hartree–Fock potential. It was found that the experimental results can be very well reproduced by use of two potentials that exhibit a significantly different distance dependence, when properly scaled. This leads to the conclusion that care must be taken when deducing a scattering potential from comparison of experimental and simulated azimuthal scans.