Renormalized Singles with Correlation in GW Green's Function Theory for Accurate Quasiparticle Energies

We apply the renormalized singles with the correlation (RSc) Green function in the GW approximation for accurate quasiparticle (QP) energies and orbitals. The RSc Green function includes singles contributions from the associated density functional approximation (DFA) and considers correlation contributions perturbatively. GRScWRSc uses the RSc Green function as the new starting point and in the formulation of the screened interaction. GRScW0 fixes the screened interaction at the DFA level. For the calculations of ionization potentials, GRScWRSc and GRScW0 significantly reduce the starting point dependence and provide accurate results with errors around 0.2 eV. For the calculations of core-level binding energies, GRScWRSc slightly overestimates the results because of underscreening, but GRScW0 with GGA functionals provides the optimal accuracy with errors of 0.40 eV. We also show that GRScWRSc predicts accurate dipole moments. GRScWRSc and GRScW0, are computationally favorable compared with any self-consistent GW methods. The RSc approach is promising for making GW and other Green function methods efficient and robust.

Automated summary

This study applies the renormalized singles with the correlation (RSc) Green function in the GW approximation to obtain accurate quasiparticle energies and orbitals. The RSc Green function combines density functional approximation (DFA) with perturbative correlation contributions. The results show that GRScWRSc and GRScW0 significantly reduce starting point dependence and provide accurate predictions for ionization potentials and core-level binding energies.