One-Electron Energies from the Two-Component GW Method

The two-component extension of the G(0)W(0) method for closed-shell systems based on the previously implemented one-component version in TURBOMOLE that uses localized basis functions is presented. In this way, it is possible to account for spin-orbit effects on one-electron energies of isolated molecular systems at the G(0)W(0) level. We briefly sketch the derivation of the underlying equations, give details about the implementation, and apply the method to several atomic and diatomic systems. The influence of spin-orbit coupling changes calculated first ionization energies by up to 0.7 eV, leading to maximum errors smaller than 0.3 eV. Virtually the same results are obtained with an economic extrapolation scheme based on the one-component G0W0 and the two-component reference state calculation. Furthermore, for binding energies of core levels, two-component G(0)W(0) is very accurate, as demonstrated for mercury and zinc atoms as well as for ZnF2.