Evaluation of electron capture distances of the Rydberg ion-surface interactions

Abstract

The theoretical research of the electron capture dynamics is essential for describing a variety of ion-surface processes. We analyze the intermediate stages of the population of the Rydberg states (n A ?1, l A =0−2) of highly charged ions escaping metal surface in the normal geometry by using the two-wave-function (TWF) method. Within the framework of the proposed timesymmetrized quantum model, the state of a single active electron is described by two wave functions r t , 1 Y  ( ) and r t , 2 Y  ( ), evolving continuously and causally from a fixed initial state of the past (t=t in ) and from a fixed final state of the future (t=t fin ), respectively. A TWF method of the single active electron in the ion-surface system has been extended and applied to analyze the population of the highly charged Rydberg ions at intermediate ionic velocities (v≈1 a.u.). The obtained rates demonstrate that the neutralization is unstable near the surface, indicating that additional reionization process is very active and completely destroy previously populated states. At larger ion-surface distances the population process is stabilized and allows estimation of the neutralization distances. The results are compared with the coupled-angular-mode method as well as with the values calculated by using the first-order transition rates and the classical overthe-barrier predictions.