RESONANT CHARGE-TRANSFER IN GRAZING ATOM-METAL SURFACE COLLISIONS - EFFECT OF THE PRESENCE OF STEPS ON THE SURFACE

The resonant charge transfer process between an atom and a metal surfa ce is studied in the case of a stepped surface. A sudden approximation is introduced to model the effect of steps in the dynamics of the cha rge transfer process for grazing angle collisions. It is applied to th e problem of H- formation by scattering on AI(111) surfaces. The final H- fractions are demonstrated to be very sensitive to the density of steps on the surface. A large difference between the effect of steps u p and down is found. The analysis of this phenomenon is performed. The results are compared with the experimental results of Wyputta et al. [Nucl. Instrum. Methods B 58 (1991) 379].