Elastic and inelastic processes in the scattering of positive ions of hydrogen and helium from a LiF surface

M. C. TORRALBA; C. M. SLUTZKY; GARCIA E.

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

The American Physical Society

Año: 2001 vol. 63 p. 1954111 - 19541110

0163-1829

A theoretical calculation that allows for a fairly complete description of the charge-exchange and surfaceelectronic excitation processes occurring in the H1 and He1 scattering by ionic surfaces is presented. Theinteraction parameters required to describe the collisional process are calculated by using a model Hamiltonianthat has proved to provide a systematic good description of the properties like binding energy, equilibriumdistance, and vibrational frequency of several dimers and atom-surface systems. The formalism is applied tothe comparative study of the scattering of H1 and He1 by the fluorine atom of a LiF surface. The ion survivalprobabilities by elastic and inelastic processes are calculated, and the general trends of the experimentalfindings are reproduced. Very satisfactory results concerning the electron-hole pair excitations in the He1scattering are obtained when the charge fluctuation on the active F site is considered. The role of the surfacecore states is found to be decisive for the e-h pair excitation by He1 scattering, and for the neutralization ofH1 projectiles.