EFFECT OF IMPURITY ON ION NEUTRALIZATION

The influence of a substitutional impurity atom on the ion neutralization near the (100) surface of a simple cubic substrate is investigated using the Green's-function method. Ion neutralization is studied within the framework of the approximate many-level method. The pure metal substrate is described by the three-dimensional tight-binding scheme, and the impurity is described by the Koster-Slater model. The effects of the impurity site, orbital energy, and impact site on ion neutralization are discussed in detail. Calculations show that the ion occupancy depends strongly on the impact site, and the impurity can play a potentially dominant role in surface-ion neutralization.