Relativity, electron correlation and QED effects in the 1s2s2 2S1/2 state of highly charged Li-like ions

On the basis of a multiconfiguration Dirac-Fock method, a systematic study has been carried out for the decay process of the 1s2s(2) 2S(1/2) state of Li-like ions. It is found that the decay properties of these states are quite different along the isoelectronic sequence: for low-Z ions up to Z = 30, the Auger decay channel is dominant; for medium-Z ions up to Z = 80, a two-electron one-photon radiative decay caused by a strong electron correlation becomes a competitive channel; and for very heavy ions about Z = 90, the magnetic dipole radiative decay becomes important too. In addition, the QED contributions to the excitation energy and the contributions from the Breit interaction to the Auger decay rates are stressed for heavy ions in particular.