Model calculation of the charge transfer in low-energy He+ scattering from metallic surfaces

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

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

The American Physical Society

Año: 1995 vol. 52 p. 16924 - 16932

0163-1829

Charge-transfer mechanisms in low-energy helium-scattering spectroscopy are analyzed by using anAnderson-like description of the time-dependent collisional process, which allows us to include several electronicbands of extended and localized nature in the solid. The Hamiltonian parameters are obtained from aHartree-Fock self-consistent-field calculation of the He-target atom dimeric system. We examine in particularcases such as Ca and Ga linear chain substrates. We found that at velocities large enough, the localized state inthe solid contributes to the He+ neutralization, showing the characteristic oscillatory behavior of the nonadiabaticcharge exchange between localized states, in agreement with other calculations. In the range of lowvelocities we found that if the hybridization between the He orbital and the localized states in the solid is ableto produce the formation of an antibonding state having a predominant weight of the He-1s orbital, thispromotes the charge exchange between the Helium and the extended bandstates of the solid