Resonant multielectron transfer in solid oxides following double K-shell ionization by heavy-ion impact

The Kα hypersatellite spectra of oxygen, obtained by bombardment of various solid oxides with 2-MeV/amu beams of C and Ar ions, were measured using a curved-crystal spectrometer. In the spectra for the compounds CaO, SrO, CeO2, and three of the oxides of Ti, some of the hypersatellite peaks appeared to be enhanced while others were suppressed. These features are indicative of resonant electron transfer processes caused by the energy matching of valence levels in the multiply ionized oxygen ion with those of its neighboring metal ions. In all cases except CaO, the spectra suggest that correlated multielectron transfer is involved, in which as many as four electrons are exchanged between the two ions. A method developed previously for estimating the energy change associated with the electron exchange was generalized to cover multielectron transfer, and corrections for extra-atomic relaxation were included. Calculations employing this method strongly support the resonant multielectron transfer hypothesis