Correlation energies for He isoelectronic sequence with Z=2-116 from four-component relativistic configuration interactions

The relativistic correlation energies (CEs) for the He isoelectronic sequence from ₂He to ₁₁₆Uuh were investigated using configuration-interaction (CI) calculations. We used a large universal-type Gaussian basis set, which gives accurate Dirac-Fock total energies for the ions under consideration. In contrast to nonrelativistic CEs, the relativistic CEs decrease monotonically with increasing nuclear charge, but the p-, d-, and f-partial CEs have a hump like the relativistic Hylleraas CI.