Relativistic all-electron two-component self-consistent density functional calculations including one-electron scalar and spin-orbit effects

A Gaussian basis-set two-component self-consistent field method based on the fourth-order nuclear-only Douglas-Kroll-Hess approximation was described. Two-electron spin-orbit effects were included using Boettger's screened-nuclear spin-orbit approximation. Approximate solutions for the Direct-Hartee-Fock or Dirac-Kohn-Sham equations involve four-component spinors built in terms of a large and a small component. The results for D _e with the hybrid PBEO yields errors similar to those obtained with first and second row elements.