Dynamics of metastable-atom deexcitation at metal surfaces

Theoretical calculations of energy levels and widths are presented that indicate that He($2^3$S) atoms are sufficiently long lived near a metal surface that a significant fraction of the excited atoms contained in a thermal-energy beam can survive passage to within ∼3–4 Å of the surface, where, it is suggested, Auger deexcitation might compete effectively with resonance ionization. This might account for earlier observations that electrons ejected from high-work-function metal surfaces by electron-spin-polarized He($2^3$S) metastable atoms have a significant spin polarization.