Journal Article

PUBDB-2016-03063

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Static Correlation and Electron Localization in Molecular Dimers from the Self-Consistent RPA and $GW$ Approximation

Hellgren, M. (Corresponding author) ; Caruso, F. ; Rohr, D. R. ; Ren, X. ; Rubio, A.CFEL*MPG* ; Scheffler, M.Extern* ; Rinke, P.

2015
APS College Park, Md.

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Please use a persistent id in citations: doi:10.1103/PhysRevB.91.165110

Abstract: We investigate static correlation and delocalization errors in the self-consistent GW and random-phase approximation (RPA) by studying molecular dissociation of the H$_2$ and LiH molecules. Although both approximations contain topologically identical diagrams, the nonlocality and frequency dependence of the GW self-energy crucially influence the different energy contributions to the total energy as compared to the use of a static local potential in the RPA. The latter leads to significantly larger correlation energies, which allow for a better description of static correlation at intermediate bond distances. The substantial error found in GW is further analyzed by comparing spin-restricted and spin-unrestricted calculations. At large but finite nuclear separation, their difference gives an estimate of the so-called fractional spin error normally determined only in the dissociation limit. Furthermore, a calculation of the dipole moment of the LiH molecule at dissociation revealsa large delocalization error in GW making the fractional charge error comparable to the RPA. The analyses are supplemented by explicit formulas for the GW Green’s function and total energy of a simplified two-level model providing additional insights into the dissociation limit.

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Contributing Institute(s):

1. Forschungsgruppe für strukturelle Dynamik (MPSD)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)
2. DYNAMO - Dynamical processes in open quantum systems: pushing the frontiers of theoretical spectroscopy (267374) (267374)
3. CRONOS - Time dynamics and ContROl in naNOStructures for magnetic recording and energy applications (280879) (280879)

Experiment(s):

1. No specific instrument

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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