Evidence for Pauli Exchange Leading to Excited-State Enhancement in Electron Transfer

Abstract

Single- and double-electron transfer to autoionizing $1s2l2{l}^{\ensuremath{'}}$ configurations in fluorine ions have been investigated for $1.1\text{ }\text{ }\mathrm{MeV}/u$ collisions of ${F}^{7+}$ and ${F}^{8+}$ with He and Ne. The resulting Auger electron emission spectra show anomolously large intensities for the formation of the metastable $1s(2s2p\text{ }^{3}P)\text{ }^{4}P$ state compared to the similarly configured $1s(2s2p\text{ }^{3}P)\text{ }^{2}P_{\ensuremath{-}}$ and $1s(2s2p\text{ }^{1}P)\text{ }^{2}P_{+}$ states. The large $^{4}P$ intensity, which cannot be explained on the basis of spin statistics, is attributed instead to the Pauli exchange of similarly aligned electrons.