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Levels of self-consistency in the GW approximation

Domenii publicaţii > Fizica + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Adrian Stan, Nils Erik Dahlen and Robert van Leeuwen

Editorial: Journal of Chemical Physics, 130, p.114105, 2009.


We perform GW calculations on atoms and diatomic molecules at different levels of self-consistency and investigate the effects of self-consistency on total energies, ionization potentials and on particle number conservation. We further propose a partially self-consistent GW scheme in which we keep the correlation part of the self-energy fixed within the self-consistency cycle. This approximation is compared to the fully self-consistent GW results and to the GW0 and the G0W0 approximations. Total energies, ionization potentials and two-electron removal energies obtained with our partially self-consistent GW approximation are in excellent agreement with fully self-consistent GW results while requiring only a fraction of the computational effort. We also find that self-consistent and partially self-consistent schemes provide ionization energies of similar quality as the G0W0 values but yield better total energies and energy differences.

Cuvinte cheie: GW fixed correlation, GWA, fully self-consistent GW approximation, atoms, molecules, total energies, ionization potentials