First-principles self-interaction free GWΓ simulations for first ionization potentials and electron affinities

We demonstrated self-interaction-free GWΓ simulations in a one-shot framework by using a Hartree-Fock approximation (HFA) as a reference and incorporating self-interaction corrections to the GW and GWΓ terms. This method is applied to simulate the first ionization potentials (IPs) and electron affinities (EAs) of 24 middle-sized molecules, yielding good agreement with available experimental data. Compared with simulations using the local density approximation (LDA) reference, the computational accuracy of the present method improved by ∼0.1 eV for IPs and 0.97 eV for EAs. The HFA reference reduces the contributions of the GW and Γ terms by 15%-38% and 65%-81%, respectively, compared with the LDA reference. Correspondingly, the self-interaction contributions in the GW and GWΓ methods are also reduced in HFA-reference simulations. However, self-interaction corrections to the Γ term remain important for achieving accurate results, as in the LDA-reference simulations.