CHARGE-EXCHANGE IN MANY-BODY TIME-DEPENDENT PROCESSES

Dynamical processes involving charge exchange between atoms and solid surfaces are studied within an Anderson-Newns model. We performed a perturbative treatment of the correlation term starting from a time-dependent Hartree-Fock basis, and calculated the probabilities of the final atomic charge states by using the Green-function formalism for irreversible processes. We analyzed the negative-ion fraction, assuming an Anderson symmetric case, and considering the electronic correlation effects up to a second perturbative order, for two "extreme" model systems: the two-level one, and a solid within the wide-band approximation.