Magnetic Interactions in Relativistic Two Particle Systems

The magnetic interactions of the two electrons in helium-like ions are studied in detail within the framework of Relativistic Schroedinger Theory (RST). The general results are used to compute the ground-state interaction energy of some highly-ionized atoms ranging from germanium (Z=32) up to bismuth (Z=83). When the magnetic interaction energy is added to its electric counterpart resulting from the electrostatic approximation, the present RST predictions reach a similar degree of precision (relative to the experimental data) as the other theoretical approaches known in the literature. However since the RST magnetism is then treated only in lowest-order approximation, further improvements of the RST predictions seem possible.