On the "killer condition" in the equation-of-motion method: Ionization potentials from multi-reference wave functions

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6 Citations (Scopus)

Abstract

The ionization operator Ω in the equation-of-motion (EOM) method is written in a form that satisfies the "killer condition" ΩT0〉 = 0 for arbitrary multiconfiguration reference states. The resulting equation for ionization potential is equivalent to traditional EOM equation only if the reference state is an exact eigenfunction of the Hamiltonian. The new equation is insensitive to specifying either a simple metric or the "commutator metric", and it represents a Hermitian formulation even for partially optimized wave functions. It is, however, equivalent to a multi-reference CI equation for the ionized state using the extended Koopmans ansatz.

Original languageEnglish
Pages (from-to)696-701
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume3
Issue number5
DOIs
Publication statusPublished - 2001

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Ionization potential
Wave functions
ionization potentials
Equations of motion
equations of motion
wave functions
Electric commutators
Hamiltonians
commutators
Eigenvalues and eigenfunctions
Ionization
Mathematical operators
eigenvectors
formulations
ionization
operators

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Atomic and Molecular Physics, and Optics

Cite this

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title = "On the {"}killer condition{"} in the equation-of-motion method: Ionization potentials from multi-reference wave functions",
abstract = "The ionization operator Ω in the equation-of-motion (EOM) method is written in a form that satisfies the {"}killer condition{"} ΩT|Ψ0〉 = 0 for arbitrary multiconfiguration reference states. The resulting equation for ionization potential is equivalent to traditional EOM equation only if the reference state is an exact eigenfunction of the Hamiltonian. The new equation is insensitive to specifying either a simple metric or the {"}commutator metric{"}, and it represents a Hermitian formulation even for partially optimized wave functions. It is, however, equivalent to a multi-reference CI equation for the ionized state using the extended Koopmans ansatz.",
author = "Z. Szekeres and A. Szabados and M. K{\'a}llay and P. Surj{\'a}n",
year = "2001",
doi = "10.1039/b008428j",
language = "English",
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pages = "696--701",
journal = "Physical Chemistry Chemical Physics",
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publisher = "Royal Society of Chemistry",
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T1 - On the "killer condition" in the equation-of-motion method

T2 - Ionization potentials from multi-reference wave functions

AU - Szekeres, Z.

AU - Szabados, A.

AU - Kállay, M.

AU - Surján, P.

PY - 2001

Y1 - 2001

N2 - The ionization operator Ω in the equation-of-motion (EOM) method is written in a form that satisfies the "killer condition" ΩT|Ψ0〉 = 0 for arbitrary multiconfiguration reference states. The resulting equation for ionization potential is equivalent to traditional EOM equation only if the reference state is an exact eigenfunction of the Hamiltonian. The new equation is insensitive to specifying either a simple metric or the "commutator metric", and it represents a Hermitian formulation even for partially optimized wave functions. It is, however, equivalent to a multi-reference CI equation for the ionized state using the extended Koopmans ansatz.

AB - The ionization operator Ω in the equation-of-motion (EOM) method is written in a form that satisfies the "killer condition" ΩT|Ψ0〉 = 0 for arbitrary multiconfiguration reference states. The resulting equation for ionization potential is equivalent to traditional EOM equation only if the reference state is an exact eigenfunction of the Hamiltonian. The new equation is insensitive to specifying either a simple metric or the "commutator metric", and it represents a Hermitian formulation even for partially optimized wave functions. It is, however, equivalent to a multi-reference CI equation for the ionized state using the extended Koopmans ansatz.

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