Ion neutralization dynamics in gracing incidence proton-surface collisions

Abstract

A semi classical close-coupling theory for electron capture in ion-surface collisions is presented. In a first application the time-dependent Schrödinger equation is solved in a basis state expansion of the conduction band and the n= 1,2,3 states on hydrogen in grazing angle incidence proton-Cu(110) collisions at 0.25 and 1.0 keV. Numerical calculations show that the neutralization probabilities oscillate as in low energy ion-atom collisions up to maximum distance of 4 a.u., leaving the nearest resonant level, n= 2, as the dominant final state. Studies of the electron dynamics show that on the incoming part of the trajectory an excited n= 3 state is formed which decouples to lower projectile levels closer to the turning point. The populated states mix strongly up to a maximum distance of around 15–20 a.u. on the outgoing trajectory