Electron-capture cross sections from atoms to hydrogen-like projectiles

Abstract

State-selective total and projectile angular-differential cross sections for single-electron transfer to the ground state from atoms in collisions with hydrogen-like projectiles are calculated by means of the four-body distorted wave approximation in the energy range from 25 to 2500 keV amu−1. In the initial channel, the effect of the dynamic electron–electron correlation is explicitly taken into account through the complete perturbation potentials. Distortion in the initial channel due to the Coulomb continuum states of the target and the active electron in the field of the residual projectile ion is included. The quantum-mechanical prior and post transition amplitudes for single-electron capture for symmetric and asymmetric collisions are then derived in terms of three-dimensional real integrals. The role of dynamic inter-electron correlation on the cross sections as a function of the impact energy is examined. Only for He+–He collisions, the projectile angular-differential cross sections for ground state capture are calculated at different impact energies. We investigate the effect of the total cross section as well as the projectile angular-differential cross sections to the choice of different ground state wavefunction of the projectile in the final state. It is observed that although the shape of the differential cross section does not change significantly for these functions, there is a significant change of the differential cross sections due to the choice of the target description. The differential cross section reveals pronounced minima and maxima in the projectile scattering angles as the projectile energy decreases. The observed structure demonstrates the analogy of atomic de Broglie’s matter-wave scattering and Fraunhofer-type diffraction. Finally the validity of our results is assessed by comparison with available experimental data.