Nonexponential decay profile of the2S13state of He-like ions

Abstract

A mechanism is proposed which explains the nonexponential decay $2{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}\to 1{}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}+\gamma \mathrm{}\left(M1\mathrm{}\right)\mathrm{}$ recently observed in beam-foil experiments on He-like atoms. This mechanism suggests that the nonexponential nature of this decay is due to the inclusion of unresolved $M1\mathrm{}$ satellite photons from Li-like ions. By using models of excited-state populations which are suggested by recent beam-foil experiments, we are able to calculate a decay profile of heliumlike sulfur which agrees with the experimental results.