THEORETICAL DESCRIPTION OF QUASI-RESONANT CHARGE-EXCHANGE IN ATOM-SURFACE COLLISIONS

Many recent ion-surface scattering experiments, e.g., He+ --> Pb, show dramatic oscillations of the neutralization probability as a function of the inverse ion velocity. These oscillations are qualitatively sim ilar to the Stueckelberg oscillations that occur during quasiresonant charge exchange in atom-atom collisions. We present here a general man y-body approach for the description of such charge-exchange processes near surfaces. We show that for the proper understanding of the oscill atory behavior it is crucial to include intra-atomic correlation effec ts. The interference between different tunneling channels influences b oth the amplitude and the frequency of these oscillations.