Transition frequencies between the 2S and 2P states of the lithiumlike ion O5+

Abstract

The Schr\odinger equation for the $2S$ state and $2P$ state of the lithiumlike ion ${\mathrm{O}}^{5+}$ is solved by using the Rayleigh-Ritz variational method in Hylleraas coordinates. The leading-order relativistic and QED corrections are calculated perturbatively and higher-order corrections are estimated approximately. The transition frequencies between the $2{S}_{1/2}$ and $2{P}_{J}$ ($J=1/2,3/2$) states, as well as the fine-structure splitting between the $2{P}_{1/2}$ and $2{P}_{3/2}$ states, are determined and compared with experimental results.