Relativistic density functional theory with finite-light-speed correction for the Coulomb interaction: a non-relativistic-reduction based approach

The Breit correction, the finite-light-speed correction for the Coulomb interaction of the electron-electron interaction in $O\left(1\mathrm{/}{c}^2\right)$, is introduced to density functional theory (DFT) based on the non-relativistic reduction with the local density approximation. Using this newly developed relativistic DFT, it is found that the possible outer-most electron of lawrencium atom is the $p$ orbital instead of the $d$ orbital, which is consistent with the previous calculations based on wave-function theory. A possible explanation of the anomalous behavior of its first ionization energy is also given. This DFT scheme provides a practical calculation method for the study of properties of super-heavy elements.