Inner-shell electron capture mechanisms in slow He2++CO and O7++COcollisions

Electron capture in slow He2+ + CO and O7+ + CO collisions has been studied using Auger electron spectroscopy. Electrons ranging from 1 to 500 eV were detected. In addition to the Auger electrons originating from the projecti le following multiple electron capture, Auger electrons are emitted from th e CO target. For the system O7+ + CIO, K Auger electrons of the CO target a re observed, providing evidence for a core excitation of the target. In con trast with collisions involving O7+ projectiles, no CO-K Auger emission app ears in He2+ + CO collisions. Hence, for He2+ + CO collisions, no target-co re excitation has been observed. However, Auger electrons whose energies ar e lower than 10 eV are observed, originating from the capture of 3 sigma in ner valence electrons from CO. In addition to the capture of these electron s, it is shown that the target may be left in highly excited states. The pr esent results are understood using simple orbital diagrams.