Singlet to Triplet Conversion of Ne2p4Core Configuration at Metal Surfaces

The relative intensities of the Ne $2p^4\left({}_{}{}^3{}_{}{}^{}P\right)3\mathrm{}{s}^2{}_{}{}^3{}_{}{}^{}P$ and $2p^4\left({}_{}{}^1{}_{}{}^{}D\right)3\mathrm{}{s}^2{}_{}{}^1{}_{}{}^{}D$ autoionization lines produced by 700 eV ${\mathrm{Ne}}^{+}$ ion impact on Na deposited on polycrystalline Al and Mo show a sensitive dependence on Na coverage. We show that the collisionally excited Ne $2p^4$ singlet core configuration can be efficiently converted to a triplet at the immediate vicinity of the excitation site, and that its rate depends strongly on the local electronic properties around the target atomic site. These findings point to a technique to obtain site-specific information of the electronic structure and potentials outside surfaces.