A 50‐Year Historical Perspective of the Extended Koopmans' Theorem, Its Exactness, and Future Prospects.
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| Title: | A 50‐Year Historical Perspective of the Extended Koopmans' Theorem, Its Exactness, and Future Prospects. |
|---|---|
| Authors: | Morrison, Robert C.1 (AUTHOR) morrisonr@ecu.edu |
| Source: | International Journal of Quantum Chemistry. 7/5/2026, Vol. 126 Issue 13, p1-5. 5p. |
| Subjects: | Ionization energy, Density matrices, Reactivity (Chemistry), Electron configuration, Atomic orbitals, Self-consistent field theory |
| Abstract: | The early history of the extended Koopmans' theorem is reviewed. Two research groups independently developed the extended Koopmans' theorem to calculate ionization energies from density matrices. Initially it was implemented for full configuration interaction and multi‐configurational self‐consistent field wave functions. Later it was implemented using other optimization methods. The long history of studies of the exactness of the extended Koopmans' theorem for ionization is discussed, as well as limits of accuracy for electron affinities. Its utility in obtaining Dyson orbitals for application in studies of chemical reactivity, for which orbital models have been instrumental to our understanding of chemical reactions, is discussed. [ABSTRACT FROM AUTHOR] |
| Copyright of International Journal of Quantum Chemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 195096466 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A 50‐Year Historical Perspective of the Extended Koopmans' Theorem, Its Exactness, and Future Prospects. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Morrison%2C+Robert+C%2E%22">Morrison, Robert C.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> morrisonr@ecu.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22International+Journal+of+Quantum+Chemistry%22">International Journal of Quantum Chemistry</searchLink>. 7/5/2026, Vol. 126 Issue 13, p1-5. 5p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Ionization+energy%22">Ionization energy</searchLink><br /><searchLink fieldCode="DE" term="%22Density+matrices%22">Density matrices</searchLink><br /><searchLink fieldCode="DE" term="%22Reactivity+%28Chemistry%29%22">Reactivity (Chemistry)</searchLink><br /><searchLink fieldCode="DE" term="%22Electron+configuration%22">Electron configuration</searchLink><br /><searchLink fieldCode="DE" term="%22Atomic+orbitals%22">Atomic orbitals</searchLink><br /><searchLink fieldCode="DE" term="%22Self-consistent+field+theory%22">Self-consistent field theory</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The early history of the extended Koopmans' theorem is reviewed. Two research groups independently developed the extended Koopmans' theorem to calculate ionization energies from density matrices. Initially it was implemented for full configuration interaction and multi‐configurational self‐consistent field wave functions. Later it was implemented using other optimization methods. The long history of studies of the exactness of the extended Koopmans' theorem for ionization is discussed, as well as limits of accuracy for electron affinities. Its utility in obtaining Dyson orbitals for application in studies of chemical reactivity, for which orbital models have been instrumental to our understanding of chemical reactions, is discussed. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of International Journal of Quantum Chemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1002/qua.70247 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 5 StartPage: 1 Subjects: – SubjectFull: Ionization energy Type: general – SubjectFull: Density matrices Type: general – SubjectFull: Reactivity (Chemistry) Type: general – SubjectFull: Electron configuration Type: general – SubjectFull: Atomic orbitals Type: general – SubjectFull: Self-consistent field theory Type: general Titles: – TitleFull: A 50‐Year Historical Perspective of the Extended Koopmans' Theorem, Its Exactness, and Future Prospects. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Morrison, Robert C. IsPartOfRelationships: – BibEntity: Dates: – D: 05 M: 07 Text: 7/5/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00207608 Numbering: – Type: volume Value: 126 – Type: issue Value: 13 Titles: – TitleFull: International Journal of Quantum Chemistry Type: main |
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