title: Bond breaking and bond formation: how electron correlation is captured in many-body perturbation theory and density-functional theory.
abstract: For the paradigmatic case of H(2) dissociation, we compare state-of-the-art many-body perturbation theory in the GW approximation and density-functional theory in the exact-exchange plus random-phase approximation (RPA) for the correlation energy. For an unbiased comparison and to prevent spurious starting point effects, both approaches are iterated to full self-consistency (i.e., sc-RPA and sc-GW). The exchange-correlation diagrams in both approaches are topologically identical, but in sc-RPA they are evaluated with noninteracting and in sc-GW with interacting Green functions. This has a profound consequence for the dissociation region, where sc-RPA is superior to sc-GW. We argue that for a given diagrammatic expansion, sc-RPA outperforms sc-GW when it comes to bond breaking. We attribute this to the difference in the correlation energy rather than the treatment of the kinetic energy.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Caruso
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany and Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Rohr
authors.affiliation: International School for Advanced Studies (SISSA), via Bonomea 265, 34136 Trieste, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Hellgren
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Xinguo
authors.initials: X
authors.lastname: Ren
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Rinke
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany and Nano-Bio Spectroscopy group and ETSF Scientific Development Centre, Universidad del País Vasco, CFM CSIC-UPV/EHU-MPC and DIPC, Avenida de Tolosa 72, E-20018 Donostia, Spain and European Theoretical Spectroscopy Facility.
authors.forename: Angel
authors.initials: A
authors.lastname: Rubio
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Scheffler
mesh_terms: D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D008956:Models, Chemical; D013816:Thermodynamics
chemical_list: D006859:Hydrogen