Charge transfer of keV-energy H+ ions in grazing scattering on Cu(100)

Abstract

An experimental study of 0.5-5.0 keV-energy H+ ion scattering on Cu(100) has been presented at a grazing scattering angle of 7°. The velocity dependent ion fractions have been measured in this work. The positive-ion fraction increases with the increase of incident velocity, which can be described by the exponential scaling. In particular, the threshold velocity for the positive-ion fraction is observed at about 0.25 a.u., and explained by the Auger ionization process. The negative-ion fraction increases monotonically with the impact velocity, which can be explained by the first type of the parallel velocity effect. Considering the formation of positive ions and the contribution of the parallel velocity effect, the negative-ion fraction is calculated by the modified theoretical model and the general trend is consistent with the experimental data.