Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach

Teale, Andrew M.; Proft, Frank De; Geerlings, Pau̧l; Tozer, David J.

doi:10.1039/c3cp54528h

Cited by 13 publications

(13 citation statements)

References 72 publications

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“…[ 39 ] Janak's theorem is commonly viewed as an analog of Koopman's theorem. [ 44 ] Only a few codes can run calculations with the core hole required for the ΔKS method. The ε(1s) method is more accessible than the ΔKS method, yet the basis set used must describe the 1s orbital, which is somehow problematic for the plane‐wave basis sets.…”

Section: Methodsmentioning

confidence: 99%

Calculation of core‐level electron spectra of ionic liquids

Lembinen

Nõmmiste

Ers

et al. 2020

Int J of Quantum Chemistry

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On the example of 40 ion pairs (5 cations times 8 anions), this study demonstrates how the core-level binding energy values can be calculated and used to plot theoretical spectra at low computational cost using density functional theory methods. Three approaches for obtaining the binding energy values are based on delta Kohn-Sham (ΔKS) calculations, 1s KS orbital energies, and atomic charges. The ΔKS results show reasonable agreement with the available experimental X-ray photoelectron data. The 1s KS orbital energies correlate well with the ΔKS results. Atomic charge correlation with ΔKS is improved by accounting for the charges of neighboring atoms. Assignment of binding energies to atoms and the applicability of the mentioned methods to model systems of ionic liquids are discussed. K E Y W O R D S core-level binding energy, delta Kohn-Sham, Green function, ionic liquid, X-ray photoelectron spectra

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Section: Methodsmentioning

confidence: 99%

Calculation of core‐level electron spectra of ionic liquids

Lembinen

Nõmmiste

Ers

et al. 2020

Int J of Quantum Chemistry

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“…Using a reasonable basis set is often used to coax an electron affinity from a standard functional when evaluating on a data base involving anions [CPR10;HSXR13]. Many authors emphasize the importance of the basis for DFT calculations of electron affinity [CHKK15;CFDH15], and some have explored the difficulties in extracting electron affinities [TDGT14]. The relation between derivative discontinuities, delocalization error and positive HOMO values is extensively explored in Ref.…”

Section: B Electron Affinitiesmentioning

confidence: 99%

The Importance of Being Inconsistent

Wasserman

Nafziger

Jiang

et al. 2017

Annu. Rev. Phys. Chem.

114

156

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We review the role of self-consistency in density functional theory. We apply a recent analysis to both Kohn-Sham and orbital-free DFT, as well as to Partition-DFT, which generalizes all aspects of standard DFT. In each case, the analysis distinguishes between errors in approximate functionals versus errors in the self-consistent density. This yields insights into the origins of many errors in DFT calculations, especially those often attributed to self-interaction or delocalization error. In many classes of problems, errors can be substantially reduced by using 'better' densities. We review the history of these approaches, many of their applications, and give simple pedagogical examples.

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Section: Ensemble Density Scalingmentioning

confidence: 99%

“…Here we have followed the arguments of King and Handy 22 in identifying the function of eqn (20) using the functional derivative of T s , this may be valid only in some (as yet to be determined) restricted sense -however, a Moreau-Yosida regularized version of this functional can be defined as prescribed in ref. 26 and its derivative coincides with the function of eqn (20) for all practical purposes as the regularization parameter is taken to be very small. Furthermore, even in the absence of regularization, we have verified numerically for standard density-functional approximations that when the function in the first term of eqn (20) is evaluated it has the same shape as Àv s , which would be expected based on the Euler eqn (21).…”

Section: Ensemble Density Scalingmentioning

confidence: 99%

“…26 and its derivative coincides with the function of eqn (20) for all practical purposes as the regularization parameter is taken to be very small. Furthermore, even in the absence of regularization, we have verified numerically for standard density-functional approximations that when the function in the first term of eqn (20) is evaluated it has the same shape as Àv s , which would be expected based on the Euler eqn (21). Throughout this work we have therefore made the usual assumption that this function can be identified using the functional derivative, and it is justified to write an Euler equation as given in eqn (21).…”

Section: Ensemble Density Scalingmentioning

confidence: 99%

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Revisiting the density scaling of the non-interacting kinetic energy

Borgoo

Teale

Tozer

2014

Phys. Chem. Chem. Phys.

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Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms.

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Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach

Cited by 13 publications

References 72 publications

Calculation of core‐level electron spectra of ionic liquids

Calculation of core‐level electron spectra of ionic liquids

The Importance of Being Inconsistent

Revisiting the density scaling of the non-interacting kinetic energy

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