Double K-Shell Vacancy Sharing in Ion-Atom Collisions

Data are presented for the two-electron one-photon (K
_aa
) decay mode of double K vacancies distributed between two collision partners. The data were generated from a variety of asymmetric heavy ion-atom systems. We propose a model for KK-vacancy sharing that predicts a double K-vacancy ratio RKK = exp(-4XK) R2K, where RK is the familiar single K-vacancy ratio. This prediction is consistent with all K
_aa
data, with recent K
^h
_a
decay mode data and also with X-ray X-ray coincidence results.