Resonant Electron Transfer in Ionic Fluorine Compounds Following1s2pIonization

The fluorine $K\alpha$ x-ray spectra produced by 5.5-MeV ${\mathrm{He}}^{+}$ bombardment of a series of alkali and alkaline-earth fluorides were measured with a curved-crystal spectrometer. An anomalously low intensity of the $K{L}^1$ peak arising from $1s^{-1\mathrm{}}{\mathrm{}\left(2s2p\right)\mathrm{}}^{-1\mathrm{}}$ initial states was observed for KF and Sr${\mathrm{F}}_2$. Evidence is presented for a resonant electron-transfer mechanism associated with the formation of a molecule-ion between adjacent cation and anion sites.