Bond Breaking and Bond Formation: How Electron Correlation is Captured in Many-Body Perturbation Theory and Density-Functional Theory

作者：Caruso Fabio^*; Rohr Daniel R; Hellgren Maria; Ren Xinguo; Rinke Patrick; Rubio Angel; Scheffler Matthias

来源：Physical Review Letters, 2013, 110(14): 146403.

DOI：10.1103/PhysRevLett.110.146403

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. DOI: 10.1103/PhysRevLett.110.146403

• 出版日期2013-4-3