Fb. Dunning et P. Nordlander, SPIN-DEPENDENT STUDIES OF THE DYNAMICS OF HE(2(3)S) ATOM DEEXCITATIONAT SURFACES, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 100(2-3), 1995, pp. 245-252
Electron spin labelling techniques provide a powerful technique with w
hich to probe the dynamics of He(2(3)S) atom deexcitation at surfaces.
Studies with a clean Cu(100) surface reveal that deexcitation occurs
exclusively through resonance ionization followed by Auger neutralizat
ion and that the electrons involved in Auger neutralization are correl
ated in spin. Model calculations suggest that this can be explained by
considering the local perturbation in the surface electronic structur
e induced by the presence of the (polarized) He+ ion. The calculated i
nduced densities of states are spin dependent and exhibit sharp Kondo-
like resonances near the Fermi level. Measurements at an adsorbed Xe f
ilm are also described and suggest that electron ejection results both
from direct Auger deexcitation (surface Penning ionization) and from
resonance ionization of incident atoms, the resulting ions being neutr
alized through an interaction that involves neighboring Xe atoms in th
e film. The Xe film data provide an unusual example of a surface at wh
ich resonance ionization and Auger deexcitation occur in parallel with
comparable rates.