Derivation of a master equation for charge-transfer processes in atom-surface collisions

The time-dependent Anderson model for multiple levels interacting with a continuum is studied using the slave-boson Green's-function technique, with an eye to understanding charge-transfer phenomena for an atomic species moving outside a metallic surface. It is shown that in the finite-temperature and low-velocity limit, the equations for the occupation numbers satisfy a master equation. Application to charge-exchange processes in atom-surface-scattering experiments shows that the presence of strong intra-atomic correlation effects can drastically change the charge-transfer dynamics.