Formation and decay of the Rydberg states of multiply charged ions interacting with solid surfaces

Abstract

Processes of formation and decay of the Rydberg states of multiply charged ions escaping solid surfaces with intermediate velocities (v ≈1 a.u.) represent complex quantum events that require a detailed quantum description. We have developed a two-state vector model for the population process, with the functions Ψ1 and Ψ2 for definition of the state of a single active electron. The electron exchange between the solid and the moving ion is described by a mixed flux through a plane positioned between them. For the low values of the angular momentum quantum numbers l the radial electronic coordinate ρ can be neglected, whereas for the large-l values a wide space region around the projectile trajectory was taken into account. The reionization of the previously populated states is considered as a decay of the wave function Ψ2. The corresponding decay rates are obtained by an appropriate etalon equation method: in the large-l case the radial electronic coordinate ρ is treated as a variational parameter. The theoretical predictions based on that population-reionization mechanism are compared with the available beam-foil experimental data, as well as the experimental data obtained in the interaction of multiply charged ions with micro-capillary foil. Generally, the model reproduces the experimentally observed non-linear trend of the l distributions from l = 0 to lmax = n - 1. © 2010 IOP Publishing Ltd.