Classical and semiclassical simulations of differential single charge exchange in fast alpha-helium collisions

Within the framework of an independent particle model, the differential single charge transfer process in the collision of fast helium ions with neutral helium targets is theoretically studied by means of the classical trajectory Monte Carlo (CTMC) method. Also, the specified reactions are investigated using two semiclassical continuum distorted wave models with eikonal initial and final states. These theories are usually identified as CDW-EIS and CDW-EFS. Using the CTMC theory, both the electron capture and the excitation probabilities are estimated and discussed as functions of the collision impact parameter. Also, the distribution of the final projectile (n, l) states and the impact parameter dependence of the electron transfer to the final n levels are investigated. Using the theories, the projectile angular distribution of the fully differential cross-sections are calculated for several impact energies in the range of 60–630 keV/u for which the experimental data are available. The obtained results are compared to each other and to their corresponding experimental values. In most of the considered cases, comparisons show that the applied treatments are in qualitative agreement with the experimental data. (paper)