Quantum electrodynamic corrections for molecules: Vacuum polarization and electron self-energy in a two-component relativistic framework.

Vacuum polarization (VP) and electron self-energy (SE) are implemented and evaluated as quantum electrodynamic (QED) corrections in a (quasi-relativistic) two-component zeroth order regular approximation (ZORA) framework. For VP, the Uehling potential is considered, and for SE, the effective potentials proposed by Flambaum and Ginges as well as the one proposed by Pyykkö and Zhao. QED contributions to ionization energies of various atoms and group 2 monofluorides, group 1 and 11 valence orbital energies, 2P1/2 ← 2S1/2 and 2P3/2 ← 2S1/2 transition energies of Li-, Na-, and Cu-like ions of nuclear charge Z = 10, 20, …, 90 as well as Π1/2 ← Σ1/2 and Π3/2 ← Σ1/2 transition energies of BaF and RaF are presented. Furthermore, perturbative and self-consistent treatments of QED corrections are compared for Kohn-Sham orbital energies of gold. It is demonstrated that QED corrections can be obtained in a two-component ZORA framework efficiently and in excellent agreement with corresponding four-component results.