The effect of point defects on the scattering and trapping of rare gases on metallic surfaces

Classical stochastic trajectory simulations with an empirical Morse potential were employed to study the effect of surface defects on the scattering and trapping of argon on Pt(1 1 1) at both thermal and structural regimes. Angular distribution patterns in the thermal regime were wide and sub-specular, while in the structural regime the patterns are sharper and centered about the specular angle. Specific features of the angular distribution curves were associated with the particular topography of the defect. Surfaces with adatoms produce broad angular distribution patterns, have higher trapping probabilities and exhibit total energy scaling behavior, while surfaces with vacancies have narrow distribution patterns, low trapping probabilities and exhibit normal scaling behavior.