Scattering of 5- to 30-keV hydrogen from surfaces

Studies have been performed of the energy distribution exhibited by recoil H+ and H- resulting from the impact of 7.5- to 15-keV H+ on targets of Be, C, Cu, Nb, Au, and stainless steel. The scattering geometry involves near grazing incidence and emergence with a scattering angle of 30.40. Peak flux occurs at higher recoil energies than in previously published studies with large-angle (1350) scattering. The energy spectrum has been shown to be in excellent agreement with the TRIM computer simulation for one case. The charge state distribution of recoils appears to be governed by charge transfer and ionization events in biparticle collisions occurring as the recoil emerges through the surface monolayer. In the study of recoil H+ fragments produced by H+2 impact there is evidence that the collision processes experienced by the fragments are in some way correlated. Recoil spectra due to D+ impact are not the same as for equal energy nor equal velocity H+ impact. The difference is explained and a simple scaling procedure suggested to relate energy spectra for the two isotopes