Spectator-electron behavior during cascade decay in krypton

We report new measurements of ${\mathrm{Kr}}^{q+}$ photo-ions, coincident with $K\ensuremath{\alpha}$ or $K\ensuremath{\beta}$ fluorescence as incident-photon energy is swept through the Kr $K$-shell threshold. From the branching ratios just above threshold, we obtain measurements of the ion charge-state probabilities for decay from the Kr $[2p]$ and Kr $[3p]$ states. In the threshold region, we observe both resonant enhancement and depletion of the branching ratios. By analyzing this behavior in light of theory, we extract sticking probabilities, which we feel are a useful set of parameters for investigating the general relationship between cascade decay from resonant and nonresonant hole states. A simplified theoretical model is employed to calculate these probabilities for the ${\mathrm{Kr}}^{2+}$ and ${\mathrm{Kr}}^{3+}$ cases.