Theoretical energy levels of $1sns$ and $1snp$ states of helium-like ions

Abstract

Energy levels of the $1sns$ and $1snp$ states of ions along the helium isoelectronic sequence from carbon to uranium are calculated, with $n=3$-$7$. The computation is performed within the relativistic configuration-interaction method, including the relativistic nuclear recoil effect, the leading QED effects, and the frequency dependence of the Breit interaction. All theoretical energies are supplied with uncertainty estimates.