2003年5月
Multireference perturbation theory with optimized partitioning. I. Theoretical and computational aspects
JOURNAL OF CHEMICAL PHYSICS
- ,
- ,
- 巻
- 118
- 号
- 18
- 開始ページ
- 8197
- 終了ページ
- 8206
- 記述言語
- 英語
- 掲載種別
- DOI
- 10.1063/1.1563618
- 出版者・発行元
- AMER INST PHYSICS
A multireference perturbation method is formulated, that uses an optimized partitioning. The zeroth-order energies are chosen in a way that guarantees vanishing the first neglected term in the perturbational ansatz for the wave function, Psi((n))=0. This procedure yields a family of zeroth-order Hamiltonians that allows for systematic control of errors arising from truncating the perturbative expansion of the wave function. The second-order version of the proposed method, denoted as MROPT(2), is shown to be (almost) size-consistent. The slight extensivity violation is shown numerically. The total energies obtained with MROPT(2) are similar to these obtained using the multireference configuration interaction method with Davidson-type corrections. We discuss connections of the MROPT(2) method to related approaches, the optimized partitioning introduced by Szabados and Surjan and the linearized multireference coupled-cluster method. The MROPT(2) method requires using state-optimized orbitals; we show on example of N-2 that using Hartree-Fock orbitals for some excited states may lead to nonphysical results. (C) 2003 American Institute of Physics.
- リンク情報
- ID情報
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- DOI : 10.1063/1.1563618
- ISSN : 0021-9606
- eISSN : 1089-7690
- Web of Science ID : WOS:000182454100009