Evaluation of the two-photon exchange graphs for the 2p(1/2)-2s transitionin Li-like ions - art. no. 032109

We present ab initio calculations of the complete gauge invariant set of th e two-photon exchange graphs for the 2p(1/2)-2s transition energy in Li-lik e high-Z ions. The evaluation is carried out to all orders in Z alpha in th e range Z = 20-100. Results are compared with calculations based on relativ istic many-body perturbation theory. All presently available contributions to the 2p(1/2)-2s transition energy are collected. The resulting theoretica l predictions are compared with experimental data.