System-dependent exchange–correlation functional with exact asymptotic potential and εHOMO ≈ − I

Gledhill, Jonathan D.; Tozer, David J.

Abstract

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.

Citation

Gledhill, J. D., & Tozer, D. J. (2015). System-dependent exchange–correlation functional with exact asymptotic potential and εHOMO ≈ − I. The Journal of Chemical Physics, 143(2), Article 024104. https://doi.org/10.1063/1.4926397

• Journal Article Type: Article
• Acceptance Date: Jun 25, 2015
• Online Publication Date: Jul 9, 2015
• Publication Date: Jul 14, 2015
• Deposit Date: Jul 13, 2015
• Publicly Available Date: Jul 23, 2015
• Journal: Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 143
• Issue: 2
• Article Number: 024104
• DOI: https://doi.org/10.1063/1.4926397
• Public URL: https://durham-repository.worktribe.com/output/1405247