Scattering of H$^{-}$ by plane and nano-stepped surfaces: Role of the ion speed for probing the surface band structure*

Resonant charge transfer between ions and metal surfaces is a useful tool to explore the surface electronic structure. Using the Crank-Nicholson propagation method [1] we solve the time-dependent Schroedinger equation to simulate the dynamic electron redistribution during the scattering of a hydrogen anion from plane and nano-stepped metal surfaces. We calculate electronic evolution during the scattering and the final ion survival probability as a function of the projectile's incident angle. We find that the survival of the ion reflected off a plane surface is very sensitive to the component of the projectile speed perpendicular to the surface and analyze rich structure of the survival probability as a function of the perpendicular speed. For the stepped surfaces, conversely, the ion survival is found to depend critically on the ion speed parallel to the surface. [1] Chakraborty et al., \textit{Phys. Rev.} A \textbf{70}, 052903 (2004).