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

The essential aspects of zero-temperature grand-canonical ensemble density-functional theory are reviewed in the context of spin-density-functional theory and are used to highlight the assumption of symmetry between electron addition and subtraction that underlies the corrected Koopmans approach of...

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Main Authors: Teale, Andrew M., De Proft, F., Geerlings, P., Tozer, David J.
Format: Article
Published: Royal Society of Chemistry 2014
Online Access:https://eprints.nottingham.ac.uk/31101/
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author Teale, Andrew M.
De Proft, F.
Geerlings, P.
Tozer, David J.
author_facet Teale, Andrew M.
De Proft, F.
Geerlings, P.
Tozer, David J.
author_sort Teale, Andrew M.
building Nottingham Research Data Repository
collection Online Access
description The essential aspects of zero-temperature grand-canonical ensemble density-functional theory are reviewed in the context of spin-density-functional theory and are used to highlight the assumption of symmetry between electron addition and subtraction that underlies the corrected Koopmans approach of Tozer and De Proft (TDP) for computing electron affinities. The issue of symmetry is then investigated in a systematic study of atomic electron affinities, comparing TDP affinities with those from a conventional Koopmans evaluation and electronic energy differences. Although it cannot compete with affinities determined from energy differences, the TDP expression yields results that are a significant improvement over those from the conventional Koopmans expression. Key insight into the results from both expressions is provided by an analysis of plots of the electronic energy as a function of the number of electrons, which highlight the extent of symmetry between addition and subtraction. The accuracy of the TDP affinities is closely related to the nature of the orbitals involved in the electron addition and subtraction, being particularly poor in cases where there is a change in principal quantum number, but relatively accurate within a single manifold of orbitals. The analysis is then extended to a consideration of the ground state Mulliken electronegativity and chemical hardness. The findings further emphasize the key role of symmetry in determining the quality of the results.
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spelling nottingham-311012020-05-04T16:42:23Z https://eprints.nottingham.ac.uk/31101/ Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach Teale, Andrew M. De Proft, F. Geerlings, P. Tozer, David J. The essential aspects of zero-temperature grand-canonical ensemble density-functional theory are reviewed in the context of spin-density-functional theory and are used to highlight the assumption of symmetry between electron addition and subtraction that underlies the corrected Koopmans approach of Tozer and De Proft (TDP) for computing electron affinities. The issue of symmetry is then investigated in a systematic study of atomic electron affinities, comparing TDP affinities with those from a conventional Koopmans evaluation and electronic energy differences. Although it cannot compete with affinities determined from energy differences, the TDP expression yields results that are a significant improvement over those from the conventional Koopmans expression. Key insight into the results from both expressions is provided by an analysis of plots of the electronic energy as a function of the number of electrons, which highlight the extent of symmetry between addition and subtraction. The accuracy of the TDP affinities is closely related to the nature of the orbitals involved in the electron addition and subtraction, being particularly poor in cases where there is a change in principal quantum number, but relatively accurate within a single manifold of orbitals. The analysis is then extended to a consideration of the ground state Mulliken electronegativity and chemical hardness. The findings further emphasize the key role of symmetry in determining the quality of the results. Royal Society of Chemistry 2014-01-02 Article PeerReviewed Teale, Andrew M., De Proft, F., Geerlings, P. and Tozer, David J. (2014) Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach. Physical Chemistry Chemical Physics, 16 (28). pp. 14420-14434. ISSN 1463-9084 http://pubs.rsc.org/en/Content/ArticleLanding/2014/CP/C3CP54528H#!divAbstract doi:10.1039/C3CP54528H doi:10.1039/C3CP54528H
spellingShingle Teale, Andrew M.
De Proft, F.
Geerlings, P.
Tozer, David J.
Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title_full Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title_fullStr Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title_full_unstemmed Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title_short Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach
title_sort atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected koopmans approach
url https://eprints.nottingham.ac.uk/31101/
https://eprints.nottingham.ac.uk/31101/
https://eprints.nottingham.ac.uk/31101/