### Abstract

For the calculation of the electron correlation energy, usual Koopmans one-electron energies (used in Møller-Plesset partitioning) are replaced by energy-optimized ones to form the denominators of the many-body perturbation theory. Changing these quasiparticle energies can be interpreted as applying special level shifts to the zero-order Hamiltonian, thus it is related to the problem of partitioning in the perturbation theory. The energy functional chosen to be optimized with respect to the quasiparticle energies is the Rayleigh quotient evaluated with the first-order wavefunction Ansatz, expanded up to the third order. The resulting level shifts preserve size extensivity of the many-body perturbation theory.

Original language | English |
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Pages (from-to) | 331-339 |

Number of pages | 9 |

Journal | Collection of Czechoslovak Chemical Communications |

Volume | 68 |

Issue number | 2 |

DOIs | |

Publication status | Published - febr. 1 2003 |

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### ASJC Scopus subject areas

- Chemistry(all)

### Cite this

**Optimized quasiparticle energies in many-body perturbation theory.** / Surján, P.; Köhalmi, Dóra; Szabados, A.

Research output: Article

*Collection of Czechoslovak Chemical Communications*, vol. 68, no. 2, pp. 331-339. https://doi.org/10.1135/cccc20030331

}

TY - JOUR

T1 - Optimized quasiparticle energies in many-body perturbation theory

AU - Surján, P.

AU - Köhalmi, Dóra

AU - Szabados, A.

PY - 2003/2/1

Y1 - 2003/2/1

N2 - For the calculation of the electron correlation energy, usual Koopmans one-electron energies (used in Møller-Plesset partitioning) are replaced by energy-optimized ones to form the denominators of the many-body perturbation theory. Changing these quasiparticle energies can be interpreted as applying special level shifts to the zero-order Hamiltonian, thus it is related to the problem of partitioning in the perturbation theory. The energy functional chosen to be optimized with respect to the quasiparticle energies is the Rayleigh quotient evaluated with the first-order wavefunction Ansatz, expanded up to the third order. The resulting level shifts preserve size extensivity of the many-body perturbation theory.

AB - For the calculation of the electron correlation energy, usual Koopmans one-electron energies (used in Møller-Plesset partitioning) are replaced by energy-optimized ones to form the denominators of the many-body perturbation theory. Changing these quasiparticle energies can be interpreted as applying special level shifts to the zero-order Hamiltonian, thus it is related to the problem of partitioning in the perturbation theory. The energy functional chosen to be optimized with respect to the quasiparticle energies is the Rayleigh quotient evaluated with the first-order wavefunction Ansatz, expanded up to the third order. The resulting level shifts preserve size extensivity of the many-body perturbation theory.

KW - Configuration interaction

KW - Correlation energy

KW - Effective one-electron energies

KW - Hamiltonian

KW - Level shifts

KW - Many-body perturbation theory (MBPT)

KW - Optimized partitioning

KW - Quantum chemistry

KW - Quasiparticle energies

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UR - http://www.scopus.com/inward/citedby.url?scp=0037309499&partnerID=8YFLogxK

U2 - 10.1135/cccc20030331

DO - 10.1135/cccc20030331

M3 - Article

VL - 68

SP - 331

EP - 339

JO - ChemPlusChem

JF - ChemPlusChem

SN - 2192-6506

IS - 2

ER -