title: Benchmarking the GW Approximation and Bethe-Salpeter Equation for Groups IB and IIB Atoms and Monoxides.
abstract: Energies from the GW approximation and the Bethe-Salpeter equation (BSE) are benchmarked against the excitation energies of transition-metal (Cu, Zn, Ag, and Cd) single atoms and monoxide anions. We demonstrate that best estimates of GW quasiparticle energies at the complete basis set limit should be obtained via extrapolation or closure relations, while numerically converged GW-BSE eigenvalues can be obtained on a finite basis set. Calculations using real-space wave functions and pseudopotentials are shown to give best-estimate GW energies that agree (up to the extrapolation error) with calculations using all-electron Gaussian basis sets. We benchmark the effects of a vertex approximation (ΓLDA) and the mean-field starting point in GW and the BSE, performing computations using a real-space, transition-space basis and scalar-relativistic pseudopotentials. While no variant of GW improves on perturbative G0W0at predicting ionization energies, G0W0ΓLDA-BSE computations give excellent agreement with experimental absorption spectra as long as off-diagonal self-energy terms are included. We also present G0W0quasiparticle energies for the CuO-, ZnO-, AgO-, and CdO-anions, in comparison to available anion photoelectron spectra.
authors.affiliation: NIST Center for Neutron Research, National Institute of Standard and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Linda
authors.identifier: http://orcid.org/0000-0002-1578-6152
authors.initials: L
authors.lastname: Hung
authors.affiliation: CEA, DEN, Service de Recherches de Métallurgie Physique, Université Paris-Saclay , F-91191 Gif-sur-Yvette, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Bruneval
authors.affiliation: Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Kopinjol
authors.initials: K
authors.lastname: Baishya
authors.affiliation: Department of Physics, University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Serdar
authors.initials: S
authors.lastname: Öğüt