Multi-electron and multi-state effects in the charge transfer processes between oxygen and metal surfaces

Oxygen atoms and molecules and their negative ions have an electronic structure containing a few equivalent outer electrons. In the course of an atom (molecule)-metal surface collision, each of them can participate in charge transfer processes. It is shown that this multi-electron aspect has to be taken into account, it generates multi-state and polarization effects. The consequences for the resonant charge transfer process are discussed and two examples are discussed: polarization effects in sputtering of O ^- ions and quenching of oxygen singlet states. A generalisation to other systems and electronic structures is presented.