Relativistic ionization energies of the helium-like ions

The ionization energies of the helium-like ions with nuclear charge numbers Z (2 <= Z <= 100) are calculated within the framework of Relativistic Schrodinger Theory (RST). The corresponding energy-eigenvalue problem in the Coulomb field of a point-like fixed nucleus is worked out in detail and numerical solutions for the ground state 1s(21)S(0) are obtained. The relativistic energy functional for the isotropic bound states is studied in detail, and its value upon the constructed ground-state solutions yields the ionization energy for both cases where the electronic self-energy is either included or neglected. The combination of the RST two-particle self-energy with the one-particle Lamb shift of QED yields predictions for the ionization energies, which for the relativistic domain (high nuclear charge numbers) agree well with the experimental data.