Boson creation by an atom moving near a surface

We consider the various mechanisms for energy transfer by an atom moving in its van der Waals potential a distance z from a surface. For the exchange of either surface optical phonons at an ionic surface or surface plasmons at a metal surface we obtain transition rates which exhibit a maximum at an optimum atomic velocity and which decay exponentially with z. It is found that single-phonon events do not always dominate the exchange rate. At small z the single-quantum monopole porcess is most important but at larger z the two-quantum dipole exchange term is greater. Single-quantum transfers arising from higher-order processes in the Born series are completely negligible.