Title : Beyond the random-phase approximation for the electron correlation energy: The importance of single excitations
Language : -
Author, co-author : Ren, X. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany]
Tkatchenko, Alexandre [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany]
Rinke, P. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany]
Scheffler, M. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany]
Publication date : 2011
Journal title : Physical Review Letters
Volume : 106
Issue/season : 15
Peer reviewed : Yes (verified by ORBilu )
Audience : International
ISSN : 00319007
Keywords : [en] Correlation energy ; Electron correlation energy ; Exact exchange ; Exchange-correlation functionals ; Exchange-correlations ; Hartree-fock ; Intermolecular interactions ; Kohn-Sham orbitals ; Noncovalent ; Orbitals ; Random phase approximations ; Random-phase approximation ; Single excitation ; Total energy ; Density functional theory ; Electron correlations ; Electron density measurement ; Standards ; Correlation methods
Abstract : [en] The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice-evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals-leads to a systematic underbinding of molecules and solids. Here we demonstrate that this behavior can be corrected by adding a "single excitation" contribution, so far not included in the standard RPA scheme. A similar improvement can also be achieved by replacing the non-self-consistent EX total energy by the corresponding self-consistent Hartree-Fock total energy, while retaining the RPA correlation energy evaluated using KS orbitals. Both schemes achieve chemical accuracy for a standard benchmark set of noncovalent intermolecular interactions. © 2011 American Physical Society.
Permalink : http://hdl.handle.net/10993/25402
DOI : 10.1103/PhysRevLett.106.153003