Multiconfiguration perturbation theory: Size consistency at second order

Gnes Szabados, Z. Rolik, Gábor Tóth, P. Surján

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

A modified version of a previously elaborated multiconfiguration perturbation theory (MCPT) [Rolik J. Chem. Phys. 119, 1922 (2003)] is presented. In the modified formulation size consistency is ensured at second order in energy, by omitting projectors from the zero order Hamiltonian operator. This MCPT formulation is abbreviated as SC2-MCPT (size consistent at second order). To ensure proper separability, we also require that energy denominators are constructed as differences of some one-particle energies. A similar choice for energy denominators also renders the well-known multireference Møller-Plesset (MRMP) energy size consistent at second order. The same thing applies to the related multireference perturbation theory by Witek, Nakano, and Hirao.

Original languageEnglish
Article number114104
JournalThe Journal of Chemical Physics
Volume122
Issue number11
DOIs
Publication statusPublished - Mar 15 2005

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Hamiltonians
Mathematical operators
perturbation theory
formulations
energy
projectors
particle energy
operators

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Multiconfiguration perturbation theory : Size consistency at second order. / Szabados, Gnes; Rolik, Z.; Tóth, Gábor; Surján, P.

In: The Journal of Chemical Physics, Vol. 122, No. 11, 114104, 15.03.2005.

Research output: Contribution to journalArticle

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