Time-dependent density functional theory study of correlation in proton-helium collisions

A recent model to describe electron correlations in time-dependent density functional theory (TDDFT) studies of antiproton-helium collisions [1] is extended to deal with positively charged projectiles. The main complication is that a positively-charged projectile can capture electrons in addition to ionizing them to the continuum. As a consequence, within the TDDFT framework one needs to consider three, instead of just one, correlation integrals ($I_c$s) when formally expressing the probabilities for the occurring one- and two-electron processes in terms of the density. We discuss possible extensions of an adiabatic model for $I_c$ [2] to deal with this situation and present results for few keV to few MeV proton-helium collisions obtained from basis-generator-method calculations with microscopic response effects included [3].\\[4pt] [1] M. Baxter and T. Kirchner, Phys. Rev. A \textbf{87}, 062507 (2013).\\[0pt] [2] F. Wilken and D. Bauer, Phys. Rev. Lett. \textbf{97}, 203001 (2006).\\[0pt] [3] M. Keim \textit{et al.}, Nucl. Instr. and Meth. B \textbf{233}, 240 (2005).