Observation of resonant transfer and excitation in O/sup 5 +/ + He collisions through high resolution O/sup 0/ Auger electron spectroscopy

In this paper we present new evidence that (resonant transfer and excitation) RTE is an important mechanism for the production of Be-like doubly excited states in energetic collisions of Li-like O/sup 5 +/ ions incident on He. We have measured the cross sections for the production of Auger electrons from the decay of the (1s2s2p/sup 2/)/sup 3/D and the (1s2s2p/sup 2/)/sup 1/D states in O/sup 4 +/ in high resolution at O/sup 0/, as a function of the incident ion energy. We observe a resonant increase in the Auger cross section with a maximum at approx.13 MeV and full-width-at-half-maximum of approx.7 MeV. This feature is seen to sit on a non-resonant NTE background, which populates the same intermediate states through a two step capture and excitation process governed by the electron-nucleus Coulomb interaction. 13 ref., 3 figs.