Neutralization of H- on vicinal surfaces

Experiments [1,2] and theoretical calculations [3] for the neutralization of H- ions on metallic surfaces show a dependence on the surface morphology. The availability of nanostructured metallic surfaces motivates the study of the effects of the surface structure on the neutralization probability of H-. We discuss the results from a theoretical study of the electron charge transfer rate and neutralization probability of H- ions colliding with metal surfaces, based on a generalized Thomas- Fermi approach for the description of the equilibrium electronic structure of the surface [4]. The ion-surface scattering calculations were performed for vicinal surfaces with different step densities at ion collision energies of 1 keV. For the studied range of collision parameters and surface morphologies, our numerical results for the neutralization probability for ``step up'' and ``step down'' scattering are significantly different, and the anion is more efficiently neutralized if the out asymptote of its scattering trajectory crosses vicinal structures in ``step down'' direction. \newline [1] E.Sanchez, L.Guillemot, V.A.Esaulov, Phys. Rev. Lett. 83, 28 (1999). \newline [2] T.Hecht et al., Phys. Rev. Lett. 84, 2517 (2000). \newline [3] H.Chakaraborty, T.Niederhausen and U.Thumm, Phys. Rev. A 70, 052903 (2004); 69, 052901 (2004). \newline [4] E.Zaremba and H.C.Tso, Phys. Rev. B 59, 2079 (1999).