Scattering of a proton with the Li4 cluster: Non-adiabatic molecular dynamics description based on time-dependent density-functional theory

Graphical abstract: Two trajectories for the collision of a proton with the Lithium tetramer. On the left, the proton is scattered away, and a Li2 molecule plus two isolated Lithium atoms result. On the right, the proton is captured and a LiH molecule is created. Highlights: ► Scattering of a proton with Lithium clusters described from first principles. ► Description based on non-adiabatic molecular dynamics. ► The electronic structure is described with time-dependent density-functional theory. ► The method allows to discern reaction channels depending on initial parameters. - Abstract: We have employed non-adiabatic molecular dynamics based on time-dependent density-functional theory to characterize the scattering behavior of a proton with the Li4 cluster. This technique assumes a classical approximation for the nuclei, effectively coupled to the quantum electronic system. This time-dependent theoretical framework accounts, by construction, for possible charge transfer and ionization processes, as well as electronic excitations, which may play a role in the non-adiabatic regime. We have varied the incidence angles in order to analyze the possible reaction patterns. The initial proton kinetic energy of 10 eV is sufficiently high to induce non-adiabatic effects. For all the incidence angles considered the proton is scattered away, except in one interesting case in which one of the Lithium atoms captures it, forming a LiH molecule. This theoretical formalism proves to be a powerful, effective and predictive tool for the analysis of non-adiabatic processes at the nanoscale.