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Title: System-dependent exchange–correlation functional with exact asymptotic potential and ε{sub HOMO} ≈ − I

Density scaling considerations are used to derive an exchange–correlation explicit density functional that is appropriate for the electron deficient side of the integer and which recovers the exact r → ∞ asymptotic behaviour of the exchange–correlation potential. The functional has an unconventional mathematical form with parameters that are system-dependent; the parameters for an N-electron system are determined in advance from generalised gradient approximation (GGA) calculations on the N- and (N − 1)-electron systems. Compared to GGA results, the functional yields similar exchange–correlation energies, but HOMO energies that are an order of magnitude closer to the negative of the vertical ionisation potential; for anions, the HOMO energies are negative, as required. Rydberg excitation energies are also notably improved and the exchange–correlation potential is visibly lowered towards the near-exact potential. Further development is required to improve valence excitations, static isotropic polarisabilities, and the shape of the potential in non-asymptotic regions. The functional is fundamentally different to conventional approximations.
Authors:
;  [1]
  1. Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom)
Publication Date:
OSTI Identifier:
22489721
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 2; 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; 97 MATHEMATICAL METHODS AND COMPUTING; ANIONS; COMPARATIVE EVALUATIONS; DENSITY; DENSITY FUNCTIONAL METHOD; ELECTRONS; EXCITATION; POLARIZABILITY