Theoretical study of the recoil-ion momentum distribution for single-electron capture in fast B5+ - He collisions

The first-order Coulomb-Born approximation with the correct boundary conditions is used to investigate the recoil-ion momentum distribution of single-electron capture in fast collision of the fully stripped ions with the ground-state helium-like atoms. To this end, both the frozen core three-body (3B) and the active electron four-body (4B) versions of the theory are developed to calculate the post and prior transition amplitudes. The calculations are performed for the energetic collision of fully stripped boron ions with helium atoms as an example, and the obtained results are compared to the experimental data as well as the results of the other theories. The comparison shows that the 3B theory provides a reasonable description of the recoil-ion momentum distribution in shape but not in magnitude. However, there is a considerable difference between the results obtained from the prior and post forms of this formulation. Also, although the 4B model is closer to the reality of the problem, its results deviate significantly from the measurements, both in magnitude and shape.