Impact of the nuclear motion on the interparticle Coulombic electron capture

Interparticle Coulombic electron capture (ICEC) is an environment-enabled electron capture process by means of which a free electron can be efficiently attached to a system (i.e., ion, atom, molecule, or quantum dot). The excess electron attachment energy is simultaneously transferred to a neighboring system (the environment) which undergoes ionization. ICEC has been theoretically predicted in van der Waals and hydrogen bonded systems as well as in quantum dot arrays. The theoretical approaches employed in these works range from analytical models to ab initio electronic structure and dynamical calculations. A common assumption in these approaches is that nuclei remain fixed during ICEC. In this paper, we use full explicit electron-nuclear dynamics simulations to show that the relative nuclear motion between the two species involved in ICEC enables the electron attachment at kinetic energies of the incoming electron far below the vertical energy threshold (i.e., at the equilibrium geometry of the system). ICEC is therefore more efficient than expected.