Reference : Beyond the random-phase approximation for the electron correlation energy: The import...

	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Physics
	To cite this reference:	http://hdl.handle.net/10993/25402

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

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