Hydrogen scattering from a LiF ionic surface: Madelung potential and local environment effects

GARCIA E.; P. G. BOLCATTO; M. C. G. PASSEGGI; E. C. GOLDBERG

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

The American Physical Society

Año: 1999 vol. 59 p. 13370 - 13378

0163-1829

The negative ion formation for large angle hydrogen scattering by a LiF surface is studied within a timedependentHartree-Fock approximation of the Anderson’s model Hamiltonian. The effect of the Madelungpotential on the projectile energy level shifts is modeled by including the point-charge field of the LiFsemicrystal in the calculation of the interaction Hamiltonian parameters. Comparisons between results obtainedby a linear-chain model and a description of the solid target based on a cluster approach, allow to infer theeffects of the local environment on the charge exchange process. It is found that H2 formation is enhanced inthe hydrogen scattering by the alkali Li1 ions when the F2 nearest neighbors are included. The scattering ofH1 within a spinless picture is also analyzed for both descriptions of the target. The H-1s energy levelvariations along the trajectory, and the quasimolecular states originated by the adiabatic interaction between theprojectile state and the core states of the target, mainly determine the H1 neutralization probability and also theelectronic excitations in the solid.