Delayed x-ray emission in the Lyman and Lyman-like series of one- and two-electron oxygen

Delayed x-ray emission has been observed in highly ionized oxygen for both the $1s-np$ H-like (Lyman) and the $1s^2-1\mathrm{snp}$ (${}_{}{}^1{}_{}{}^{}S-{}_{}{}^1{}_{}{}^{}P$) He-like sequence. Within less than 0.5 nsec after formation, the shapes of the decay curves for all the measured transitions were found to be similar, each following a power-law time dependence. This nonexponential shape for the decay curves is attributed to cascade effects from states near the ionization limit.