Differential and total cross sections for charge transfer and transfer-excitation in ion-helium collisions

Abstract

Total cross sections for single charge transfer in collisions of multicharged bare ions with ground-state helium atoms at incident energy ranging from 40 to 5000 keV/amu have been calculated in the framework of a four-body model of final channel distorted-wave (FC-DW-4B) approximation. In this formalism, distortion in the final channel related to the Coulomb continuum of the target and the Coulomb interaction between the passive electron in the target with the projectile are included. In all cases, total single electron-capture cross sections have been calculated by summing over all contributions up to $n=3$ shells and subshells. It has been observed that the contribution of the capture cross sections into excited states have insignificant contributions for symmetric collisions. Comprehensive comparisons are made between the four body model of boundary corrected continuum intermediate-state approximations [Phys. Rev. A 83, 032706 (2011)] and the present FC-DW-4B model. The main purpose of the present study is to investigate the relative importance of dynamic electron correlation and the role of passive electron in the target at intermediate and high impact energies. In addition, projectile angular differential cross sections (DCS) for charge transfer and transfer-excitation in $p\text{-He}$ collisions are calculated at different impact energies. At low projectile energies, the present DCS data exhibits the typical steeply decreasing dependence on the projectile scattering angles, whereas at high impact energies, the double-scattering region centered on the Thomas angle is obtained. Detailed comparisons with the available experimental data and other theories are reported with the purpose of further assessing the relevance of the present model at different impact energies. Overall, the calculated cross sections show good agreement with the available experimental findings.