Self-consistent GW: All-electron implementation with localized basis functions

doi:10.1103/PhysRevB.88.075105

2013-08-05

151

DOI：10.1103/PhysRevB.88.075105

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This paper describes an all-electron implementation of the self-consistent GW (sc-GW) approach-i.e., based on the solution of the Dyson equation-in an all-electron numeric atom-centered orbital basis set. We cast Hedin's equations into a matrix form that is suitable for numerical calculations by means of (i) the resolution-of-identity technique to handle four-center integrals and (ii) a basis representation for the imaginary-frequency dependence of dynamical operators. In contrast to perturbative G(0)W(0), sc-GW provides a consistent framework for ground- and excited-state properties and facilitates an unbiased assessment of the GW approximation. For excited states, we benchmark sc-GW for five molecules relevant for organic photovoltaic applications: thiophene, benzothiazole, 1,2,5-thiadiazole, naphthalene, and tetrathiafulvalene. At self-consistency, the quasiparticle energies are found to be in good agreement with experiment and, on average, more accurate than G(0)W(0) based on Hartree-Fock or density-functional theory with the Perdew-Burke-Ernzerhof exchange-correlation functional. Based on the Galitskii-Migdal total energy, structural properties are investigated for a set of diatomic molecules. For binding energies, bond lengths, and vibrational frequencies sc-GW and G(0)W(0) achieve a comparable performance, which is, however, not as good as that of exact-exchange plus correlation in the random-phase approximation and its advancement to renormalized second-order perturbation theory. Finally, the improved description of dipole moments for a small set of diatomic molecules demonstrates the quality of the sc-GW ground-state density.

Keyword:

AUXILIARY BASIS-SETS

GREENS-FUNCTION

FIELD THEORY

ENERGY

APPROXIMATION

SEMICONDUCTORS

CHEMISTRY

INTEGRALS

SPECTRA

STATES