title: Benchmark Many-Body GW and Bethe-Salpeter Calculations for Small Transition Metal Molecules.
abstract: We study the electronic and optical properties of 39 small molecules containing transition metal atoms and 7 others related to quantum-dots for photovoltaics. We explore in particular the merits of the many-body GW formalism, as compared to the ΔSCF approach within density functional theory, in the description of the ionization energy and electronic affinity. Mean average errors of 0.2-0.3 eV with respect to experiment are found when using the PBE0 functional for ΔSCF and as a starting point for GW. The effect of partial self-consistency at the GW level is explored. Further, for optical excitations, the Bethe-Salpeter formalism is found to offer similar accuracy as time-dependent DFT-based methods with the hybrid PBE0 functional, with mean average discrepancies of about 0.3 and 0.2 eV, respectively, as compared to available experimental data. Our calculations validate the accuracy of the parameter-free GW and Bethe-Salpeter formalisms for this class of systems, opening the way to the study of large clusters containing transition metal atoms of interest for photovoltaic applications.
authors.affiliation: Institut Lumière Matière and European Theoretical Spectroscopy Facility, UMR5306 Université Lyon 1-CNRS, Université de Lyon , F-69622 Villeurbanne Cedex, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Körbel
authors.affiliation: Univ. Grenoble Alpes, Inst NEEL , F-38042 Grenoble, France.|CNRS, Inst NEEL , F-38042 Grenoble, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Boulanger
authors.affiliation: INAC, SP2M/L_sim, CEA cedex 09, 38054 Grenoble, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Duchemin
authors.affiliation: Univ. Grenoble Alpes, Inst NEEL , F-38042 Grenoble, France.|CNRS, Inst NEEL , F-38042 Grenoble, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Blase
authors.affiliation: Institut Lumière Matière and European Theoretical Spectroscopy Facility, UMR5306 Université Lyon 1-CNRS, Université de Lyon , F-69622 Villeurbanne Cedex, France.
authors.forename: Miguel A L
authors.initials: MA
authors.lastname: Marques
authors.affiliation: Institut Lumière Matière and European Theoretical Spectroscopy Facility, UMR5306 Université Lyon 1-CNRS, Université de Lyon , F-69622 Villeurbanne Cedex, France.
authors.forename: Silvana
authors.initials: S
authors.lastname: Botti