Lifetimes of the Metastable Auto-Ionizing(1s2s2p)P524States of LithiumlikeF6+andO5+Ions

Abstract

Electrons emitted from foil-excited beams of ${\mathrm{F}}^{6+}$ and ${\mathrm{O}}^{5+}$ ions (2.5-20 MeV) have been energy analyzed and their number measured versus distance from the foil. Lines associated with the $\mathrm{}\left(1s2s2p\right)\mathrm{}{}_{}{}^4{}_{}{}^{}P_{\frac{5}{2}}^{}{}_{}{}^{}$ level and with higher quartet levels are observed to decay at various rates. Life-times for the $\mathrm{}\left(1s2s2p\right)\mathrm{}{}_{}{}^4{}_{}{}^{}P_{\frac{5}{2}}^{}{}_{}{}^{}$ state in ${\mathrm{F}}^{6+}$ and ${\mathrm{O}}^{5+}$ are found to be (1.5 ± 0.1) and (2.5 ± 0.3) × ${10}^{-8\mathrm{}}$ sec, respectively. The latter disagrees with earlier experimental work and with theoretical estimates.