Ab Initio Study of Single- and Double-Electron Capture Processes in Collisions of He²⁺ Ions and Ne Atoms

Abstract

The single- and double-electron capture (SEC, DEC) processes of He2+ ions colliding with Ne atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling method. Total and state-selective SEC and DEC cross sections are presented in the energy region of 2 eV/u to 20 keV/u. Results show that the dominant reaction channel is Ne+(2s2p 6 2 S) + He+(1s) in the considered energy region due to strong couplings with the initial state Ne(2s 22p 6 1 S) + He2+ around the internuclear distance of 4.6 a.u. In our calculations, the SEC cross sections decrease initially and then increase whereby, the minimum point is around 0.38 keV/u with the increase of collision energies. After considering the effects of the electron translation factor (ETF), the SEC cross sections are increased by 15%–25% nearby the energy region of keV/u and agree better with the available results. The DEC cross sections are smaller than those of SEC because of the larger energy gaps and no strong couplings with the initial state. Due to the Demkov-type couplings between DEC channel Ne2+(2s22p 4 1 S) + He(1s 2) and the dominating SEC channel Ne+(2s2p 6 2 S) + He+(1s), the DEC cross sections increase with increasing impact energies. Good consistency can also be found between the present DEC and the experimental measurements in the overlapping energy region.

A Time-Dependent-Density-Functional-Theory Study of Charge Transfer Processes of Li2+ Colliding with Ar in the MeV Region

“…Charge transfer of fully stripped projectile was studied frequently due to their structural simplicity, i.e., the projectile is usually described as a classical point of charge. However, charge transfer of dressed projectiles has attracted significant interests in recent years, because the active electrons of the projectile play a role in specific processes, [7][8][9] resulting in more complicated mechanisms, such as the screening effects, [10][11][12] the enhancement of state-selected cross sections, [13,14] and stopping powers. [15] To theoretically describe the dressed projectile, the effect of its active electrons cannot be neglected.…”