LOCAL-EFFECTS OF THE ADSORBATES ON THE RESONANT ATOM-SURFACE CHARGE-TRANSFER

A theoretical study of the charge transfer process between a collision al atom and an Al surface partially covered by alkali adsorbates is pr esented. The non-perturbative Coupled Angular Mode (CAM) method is app lied to calculate the static properties of the projectile states. The energies and the widths of the projectile states are strongly modified in the vicinity of the adsorbate compared to the clean surface case. This is attributed to the molecularisation of the atomic and adsorbate levels. The dynamics of the neutralization of Li+ ions is studied in the case of backscattering from the Al sites and from the alkali sites on the surface. Large differences in the neutralisation probabilities for Li+ scattered from the substrate sites and from the adsorbate sit es are obtained. The pecularities of Li- formation in backscattering f rom alkali adsorbate sites are discussed.