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Koopmans' theorem

Koopmans' theorem proper noun: a theory stating that, in closed-shell Hartree-Fock theory, the first ionization energy of a molecular system is equal to the negative of the orbital energy of the highest occupied molecular orbital (HOMO).

Proper noun

Koopmans' theorem

  1. A theory stating that, in closed-shell Hartree-Fock theory, the first ionization energy of a molecular system is equal to the negative of the orbital energy of the highest occupied molecular orbital (HOMO).
    • There exists another approach to correct the DFT and its related Kohn-Sham Hamiltonian: the Koopmans’ theorem¹¹⁻²². The original Koopmans’ theorem only states that in Hartree-Fock, the first ionization energy is equal to the highest occupied orbital energy if the wave function relaxations are...2016 April 26, Jie Ma, Lin-Wang Wang, “Using Wannier functions to improve solid band gap predictions in density functional theory”, in Scientific Reports, volume 6, →DOI, article 24924, page 1

Origin of Koopmans' theorem

Named after Dutch-American mathematician Tjalling Koopmans (1910–1985), who published this result in 1934.

Questions about Koopmans' theorem

What does Koopmans' theorem mean?
Koopmans' theorem means a theory stating that, in closed-shell Hartree-Fock theory, the first ionization energy of a molecular system is equal to the negative of the orbital energy of the highest occupied molecular orbital (HOMO).
What part of speech is Koopmans' theorem?
Koopmans' theorem is a proper noun.

Words near Koopmans' theorem in the dictionary

  1. Koop
  2. Koopman
  3. Koopmann
  4. Koopmanns
  5. Koopmans
  6. Koopmans' theorem
  7. Koops
  8. Kooragang
  9. Koorainghat
  10. koorajong
  11. Kooranko

Source and license

Adapted from Wiktionary: Koopmans' theorem (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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