Koopmans’ Theorem in the Hartree-Fock Method. General Formulation Full article
| Journal |
Journal of Chemical Physics
ISSN: 0021-9606 , E-ISSN: 1089-7690 |
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| Output data | Year: 2018, Volume: 148, Number: 9, Article number : 094101, Pages count : 17 DOI: 10.1063/1.5019330 | ||
| Tags | self-consistent-field; direct configuration-interaction; determinant wave-functions; coupling operator method; multiple active spaces; open-shells; perturbation-theory; basis-sets; icosahedral symmetry; variable occupations | ||
| Authors |
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| Affiliations |
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Funding (2)
| 1 | Federal Agency for Scientific Organizations | 0303-2016-0001 |
| 2 | Russian Foundation for Basic Research | 15-03-00830 |
Abstract:
This work presents a general formulation of Koopmans’ theorem (KT) in the Hartree-Fock (HF)
method which is applicable to molecular and atomic systems with arbitrary orbital occupancies and
total electronic spin including orbitally degenerate (OD) systems. The newformulation is based on the
full set of variational conditions imposed upon the HF orbitals by the variational principle for the total
energy and the conditions imposed by KT on the orbitals of an ionized electronic shell [B. N. Plakhutin
and E. R. Davidson, J. Chem. Phys. 140, 014102 (2014)]. Based on these conditions, a general form
of the restricted open-shell HF method is developed, whose eigenvalues (orbital energies) obey KT
for the whole energy spectrum. Particular attention is paid to the treatment of OD systems, for which
the new method gives a number of unexpected results. For example, the present method gives four
different orbital energies for the triply degenerate atomic level 2p in the second row atoms B to F.
Based on both KT conditions and a parallel treatment of atoms B to F within a limited configuration
interaction approach, we prove that these four orbital energies, each of which is triply degenerate, are
related via KTto the energies of different spin-dependent ionization and electron attachment processes
(2p)N !(2p)N1. A discussion is also presented of specific limitations of the validity of KT in the HF
method which arise in OD systems. The practical applicability of the theory is verified by comparing
KT estimates of the ionization potentials I2s and I2p for the second row open-shell atoms Li to F with
the relevant experimental data. Published by AIP Publishing
Cite:
Plakhutin B.N.
Koopmans’ Theorem in the Hartree-Fock Method. General Formulation
Journal of Chemical Physics. 2018. V.148. N9. 094101 :1-17. DOI: 10.1063/1.5019330 WOS Scopus РИНЦ ANCAN OpenAlex
Koopmans’ Theorem in the Hartree-Fock Method. General Formulation
Journal of Chemical Physics. 2018. V.148. N9. 094101 :1-17. DOI: 10.1063/1.5019330 WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
| Submitted: | Dec 13, 2017 |
| Accepted: | Feb 9, 2018 |
| Published online: | Mar 1, 2018 |
| Published print: | Mar 7, 2018 |
Identifiers:
| Web of science: | WOS:000427030500004 |
| Scopus: | 2-s2.0-85042757323 |
| Elibrary: | 35495556 |
| Chemical Abstracts: | 2018:364703 |
| Chemical Abstracts (print): | 169:80221 |
| OpenAlex: | W2790559611 |