Electron detachment processes inH−grazing scattering from a LiF(001) surface

Electron detachment from ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ ions scattered at a grazing angle from a LiF(001) surface is studied by three-dimensional wave-packet propagation. Electron detachment is shown to be due to binary interactions between the projectile ion and the surface ${\mathrm{F}}^{\mathrm{\ensuremath{-}}}$ anions, resulting primarily in electron ejection into vacuum. The importance of the detachment rate confirms the interpretations, proposed for various collisional phenomena at ionic crystal surfaces, involving repeated electron-capture/loss cycles in grazing scattering.