Double ionization of He and Li by ion impact: Final state correlation

Abstract

The total cross-sections for atomic double ionization are evaluated with a two-step approximation, by considering that the projectile ionizes successively each electron. Single ionization probabilities are calculated within the continuum distorted-wave with eikonal initial state (CDW-EIS) formalism. The initial and final atomic wave functions are obtained by solving numerically the atomic wave equations with an optimized potential model (OPM). The electron–electron correlation in the final state is investigated following three different approaches: the usual Gamow factor, a modified Gamow factor with an effective charge and a mean value of the electron–electron repulsive Coulomb wave. The calculations are compared with experimental data and good agreement is found for double ionization of He and Li atoms by H +, He 2+and Li 3+ impact, at intermediate energies.