Interelectronic interaction contribution to the hyperfine structure of highly charged lithiumlike ions

Abstract

The hyperfine structure of highly charged lithiumlike ions is considered within QED using the $\frac{1}{Z}$ perturbation theory ($Z$ is the nuclear charge). The interelectronic interaction contribution of the order of $\frac{1}{Z}$ to the hyperfine splitting of the ground state is calculated in the range $Z=5-100\mathrm{}$. The hyperfine splitting values are found for the ground state of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}_{}^{23+}{}_{}{}^{}$ and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}_{}^{80+}{}_{}{}^{}$.