Auger neutralization of He ions on Ag surfaces: surface type and azimuthal orientation dependence

Abstract

PACS 68.49. Sf, 71.15.Pd Neutralization of He + ions in grazing incidence scattering on Ag(111) and Ag(110) surfaces is studied. These measurements reveal the existence of an order of magnitude difference in the probability of ion survival on Ag(110) and Ag(111). The effect of changing the direction of ion scattering along the surface azimuthal orientation is investigated. The experimental results are discussed in terms of survival from Auger neutralization, whose rates are derived theoretically. Molecular dynamics simulation of scattered ion trajectories are performed and the surviving ion fractions are then calculated using the theoretical Auger neutralization rates, without adjustable parameters. The calculations agree quite well with the experimental data and show that the observed differences in the neutralization probabilities on these surfaces are related to different extensions of the electron density beyond the surface, resulting from different atomic packing.

Resonant charge transfer in low-energy ion scattering: Information depth in the reionization regime

“…Ongoing research by different groups aims on a thorough understanding of the relevant charge exchange processes. A recent finding is, that the neutralization efficiency for He + scattered from single crystals with different surface orientations may differ significantly [6–11] . Experiments performed in grazing incidence can be accurately described by a theoretical model [12] .…”