Theoretical investigation of the fully differential cross sections for single ionization of He in collisions with 75-keV protons

Abstract

We present a theoretical investigation of the single ionization of He in collisions with ${\mathrm{H}}^{+}$ projectile ions at 75-keV impact energy. Using the frameworks of the independent-electron model and the impact parameter picture, fully differential cross sections (FDCS) are evaluated in the continuum distorted-wave with eikonal initial-state approximation (CDW-EIS). Comparisons are made to the recent measurements of Schulz et al. [Phys. Rev. A 73, 062704 (2006)] and Arthanayaka et al. [J. Phys. B: At. Mol. Opt. Phys. 49, 13LT02 (2016)]. Strong influence of the internuclear interaction and effects of target core polarization due to the presence of the projectile ion are observed. Comparing the present results to experimental data and other theoretical predictions, it has been found that the CDW-EIS method qualitatively reproduces structures in the FDCS. Projectile coherence effects are investigated by representing the projectile beam as a Gaussian wave packet. Evidence of interference effects due to projectile-electron and projectile-target core interactions are discussed and the need for further theoretical investigations is proposed.