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

Gledhill, Jonathan D.; Tozer, David J.

doi:10.1063/1.4926397

Cited by 13 publications

(27 citation statements)

References 57 publications

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“…Attempts have been made to model such features directly into semilocal xc potentials [34][35][36][37][38][39][40][41][42][43][44][45], partially also with an additional (nonlocal) eigenvalue dependence, e.g., as done by Gritsenko et al (GLLB) [46] and Kuisma et al [47].…”

Section: Introductionmentioning

confidence: 99%

Challenges for semilocal density functionals with asymptotically nonvanishing potentials

2017

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have been shown to mimic features of the exact Kohn-Sham exchange potential, such as step structures that are associated with shell closings and particle-number changes. A key element in the construction of these functionals is that the potential has a limiting value far outside a finite system that is a system-dependent constant rather than zero. We discuss a set of anomalous features in these functionals that are closely connected to the nonvanishing asymptotic potential. The findings constitute a formidable challenge for the future development of semilocal functionals based on the concept of a nonvanishing asymptotic constant.

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Section: Introductionmentioning

confidence: 99%

Challenges for semilocal density functionals with asymptotically nonvanishing potentials

2017

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“…32) and this can be traced to the lack of gradient dependence in the functional (as was also observed in Ref. 20). Although there is much room for improvement, the fact that the PBE potential can be reasonably reproduced by the potential of the (unconventional) second term in Eq (40) is intriguing.…”

Section: Pbe Deks Results For Comparisonmentioning

confidence: 62%

“…The key quantities in DFT are functionals of the density and in another series of papers, [14][15][16][17][18][19][20] Tozer and co-workers have studied their density scaling properties. A functional F [ρ] is said to be homogeneous of degree k F under density scaling if it satisfies…”

Section: Introductionmentioning

confidence: 99%

Approximating the Shifted Hartree-Exchange-Correlation Potential in Direct Energy Kohn–Sham Theory

Sharpe

Levy

Tozer

2018

J. Chem. Theory Comput.

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Levy and Zahariev [Phys. Rev. Lett. 113 113002 (2014)] have proposed a new approach for performing density functional theory calculations, termed direct energy Kohn-Sham (DEKS) theory. In this approach, the electronic energy equals the sum of orbital energies, obtained from Kohn-Sham-like orbital equations involving a shifted Hartree-exchange-correlation potential, which must be approximated. In the present study, density scaling homogeneity considerations are used to facilitate DEKS calculations on a series of atoms and molecules, leading to three nonlocal approximations to the shifted potential. The first two rely on preliminary Kohn-Sham calculations using a standard generalized gradient approximation (GGA) exchange-correlation functional and the results illustrate the benefit of describing the dominant Hartree component of the shift exactly. A uniform electron gas analysis is used to eliminate the need for these preliminary Kohn-Sham calculations, leading to a potential with an unconventional form that yields encouraging results, providing strong motivation for further research in DEKS theory.

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“…First we need to identify functionals that yield negative LUMO energies. An obvious choice is the original electron deficient functional proposed by GT in ref 58. We also consider a second electron deficient functional, obtained by using the same approach, but without the Fermi-Amaldi component in the functional.…”

Section: Methodsmentioning

confidence: 99%

“…The scheme uses only GGA information to estimate the exact k − xc , but it works well, yielding HOMO energies that approximately equal the negative of the ionisation potential (as required, see eq (3)). See ref 58 and Section 2 for further details.…”

Section: Introductionmentioning

confidence: 99%

Simple DFT Scheme for Estimating Negative Electron Affinities

Vibert

Tozer

2018

J. Chem. Theory Comput.

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2018) 'Simple DFT scheme for estimating negative electron anities.', Journal of chemical theory and computation., 15 (1). pp. 241-248.The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract A simple density functional theory (DFT) scheme is proposed for estimating negative vertical electron affinities of neutral systems, based on a consideration of the integer discontinuity and density scaling homogeneity. The key feature is the derivation of two system-dependent exchange-correlation functionals, one appropriate for the electron deficient side of the integer and one appropriate for the electron abundant side. The electron affinity is evaluated as a linear combination of frontier orbital energies from self-consistent Kohn-Sham calculations on the neutral system using these functionals. For two assessments comprising a total of 43 molecules, the scheme provides electron affinities that are in good agreement with experimental values and which are an improvement over those from the DFT method of Tozer and De Proft [J. Phys. Chem. A 109 8923 (2005)]. The scheme is trivial to implement in any Kohn-Sham program and the computational cost is that of a series of generalised gradient approximation Kohn-Sham calculations. More generally, the study provides a prescription for performing low-cost, self-consistent Kohn-Sham calculations that yield frontier orbital energies that approximately satisfy the appropriate Koopmans conditions, without the need for exact exchange.

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

Cited by 13 publications

References 57 publications

Challenges for semilocal density functionals with asymptotically nonvanishing potentials

Challenges for semilocal density functionals with asymptotically nonvanishing potentials

Approximating the Shifted Hartree-Exchange-Correlation Potential in Direct Energy Kohn–Sham Theory

Simple DFT Scheme for Estimating Negative Electron Affinities

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