Theoretical energies of low-lying states of light helium-like ions

A rigorous quantum electrodynamical calculation is presented for energy levels of the 1 1S, 2 1S, 2 3S, 2 1P1, and 2 3P0,1,2 states of helium-like ions with the nuclear charge Z=3,...,12. The calculational approach accounts for all relativistic, quantum electrodynamical, and recoil effects up to orders mα6 and m2/Mα5, thus advancing the previously reported theory of light helium-like ions by one order in α.