Spin dependent screening and Auger neutralization of singly-charged noble gas ions in metals

The screening of Ne+ and Ar+ ions embedded in a paramagnetic free electron gas is calculated using density functional theory within the local spin density approximation, analyzing the spin polarization of the screening cloud. As a second step, the Auger neutralization rates for these ions in a free electron gas are calculated, paying special attention to their dependence on the spin direction of the electron excited in the Auger process. It is observed that the spin polarization of the screening cloud and that of the Auger rates are related. Comparison with previous calculations performed for He+ shows that the spin polarization of the excited electrons is lower in the case of Ne+ and Ar+ than in the case of He+. This result is consistent with the experimental data obtained for the spin polarization of the emitted electrons in the deexcitation of metastable He∗, Ne∗ and Ar∗ atoms in front of metal surfaces.