2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84234We develop an Over Barrier Model for computing charge exchange between ions and one-active-electron atoms at low impact energies. The main feature of the model is the treatment of the barrier crossing process by the electron within a simplified quantum mechanical formulation which takes into account: (a) the probability of electron reflection even for over-barrier scattering, and (b) the discreteness of the receiving atom's quantum levels which strongly suppress captures far from the resonance condition. It is shown that inclusion of these effects yields a fairly good prediction of experimental data. We discuss also the probability of electron re-capture by the target.ReVTeX 4.0, 10 pages, 6 eps figures, version 2 thoroughly revisedAtomic Physicstext