Spin-dependent studies of the dynamics of He+ ion neutralization at a Au(100) surface

Spin labeling techniques, specifically the use of electron-spin-polarized H e+ ions coupled with energy-resolved measurements of the ejected electron p olarization, are used to study the dynamics of He+ neutralization at a Au(1 00) surface, A marked correlation in the spins of the electrons involved in the Anger neutralization process is observed that is particularly pronounc ed at the highest ejected electron energies. A theoretical model is present ed that explains the general characteristics of the data by considering the perturbation in the surface electronic structure induced by the presence o f the (polarized) He+ ion. This model, which includes the effects of ion ve locity parallel to the surface, shows that the induced density of states is spin dependent, the spin dependence bring most pronounced in the vicinity of the Fermi energy.