Electron transfer in ionic fluorine compounds following multiple ionization by 22-MeV carbon ions

The spectra of $K$ x rays emitted by thin targets of the alkali-metal and alkaline-earth fluorides under bombardment with 22-MeV carbon ions were measured with a curved crystal spectrometer. Comparison of the satellite intensity distributions with that obtained for neon under similar conditions revealed that electron transfer within the $K$-hole lifetime (∼ ${10}^{-13\mathrm{}}$ sec) is highly probable even for these highly ionic compounds. A detailed analysis of the satellite intensity distribution obtained for LiF yielded a rate constant for $K{L}^1-K{L}^0$ transfer equal to 30% that for $K$-vacancy decay. The spectra for KF, Sr${\mathrm{F}}_2$, and Ba${\mathrm{F}}_2$ show evidence of resonant electron transfer (RET) associated with the matching of the $2p$ binding energies of fluorine atoms in $K{L}^1$ states with the outer $\mathrm{np}$ binding energies of adjacent metal ions, in agreement with previous findings. Also, an anomalously low $K{L}^2$ intensity, indicative of RET in association with this double $L$-hole state, was observed for Ca${\mathrm{F}}_2$. An additional component contributing to the enhancement of the $K{L}^0$ peak was attributed to secondary-electron ionization.