BOUND-ELECTRON CAPTURE FROM SURFACE ATOMS BY HEAVY PROJECTILES AT GRAZING COLLISIONS

The capture of electrons bound to the atoms of a crystal surface by grazing heavy projectiles is studied in the high-energy regime. The eikonal impulse approximation is used to calculate the capture atomic probabilities, which are then folded with the distance-to-the-surface distribution given by planar channeling theory. Good agreement is found with experiments at high energies. We also study the influence of the rugosity or surface irregularities formed by adsorbed atoms. It is concluded that, in the high-energy tail, the capture of bound electrons is more important than capture from the free-electron gas. It is found that the closest distance to the surface and the rugosity play decisive roles.