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Title: Real-space representation of electron correlation in π-conjugated systems

π-electron conjugation and aromaticity are commonly associated with delocalization and especially high mobility of the π electrons. We investigate if also the electron correlation (pair density) exhibits signatures of the special electronic structure of conjugated systems. To that end the shape and extent of the pair density and derived quantities (exchange-correlation hole, Coulomb hole, and conditional density) are investigated for the prototype systems ethylene, hexatriene, and benzene. The answer is that the effects of π electron conjugation are hardly discernible in the real space representations of the electron correlation. We find the xc hole to be as localized (confined to atomic or diatomic regions) in conjugated systems as in small molecules. This result is relevant for density functional theory (DFT). The potential of the electron exchange-correlation hole is the largest part of v{sub xc}, the exchange-correlation Kohn-Sham potential. So the extent of the hole directly affects the orbital energies of both occupied and unoccupied Kohn-Sham orbitals and therefore has direct relevance for the excitation spectrum as calculated with time-dependent DFT calculations. The potential of the localized xc hole is comparatively more attractive than the actual hole left behind by an electron excited from a delocalized molecular orbital of a conjugatedmore » system.« less
Authors:
 [1] ;  [2]
  1. School of Science, Huzhou University, Zhejiang 10083 (China)
  2. Afdeling Theoretische Chemie, FEW, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam (Netherlands)
Publication Date:
OSTI Identifier:
22415874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BENZENE; DENSITY; DENSITY FUNCTIONAL METHOD; ELECTRON CORRELATION; ELECTRON EXCHANGE; ELECTRONIC STRUCTURE; ELECTRONS; ETHYLENE; EXCITATION; HOLES; MOBILITY; MOLECULAR ORBITAL METHOD; MOLECULES; POTENTIALS; TIME DEPENDENCE