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A new size extensive multireference perturbation theory
Author(s) -
Chen Feiwu,
Fan Zhihui
Publication year - 2013
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23471
Subject(s) - multireference configuration interaction , perturbation theory (quantum mechanics) , perturbation (astronomy) , chemistry , dissociation (chemistry) , atomic physics , møller–plesset perturbation theory , computational chemistry , basis set , quantum mechanics , physics , density functional theory
A new multireference perturbation series is derived based on the Rayleigh–Schrödinger perturbation theory. It is orbitally invariant. Its computational cost is comparable to the single reference Møller–Plesset perturbation theory. It is demonstrated numerically that the present multireference second‐ and third‐order energies are size extensive by two types of supermolecules composed of H 2 and BH monomers. Spectroscopic constants ofF 2 ( X 1 Σ g + ) , Cl 2 ( X 1 Σ g + ) , C 2 − ( X 2 Σ g + ) , B 2 ( X 3 Σ g − ) , and C 2 + ( X 4 Σ g − )as well as the ground state energies of H 2 O, NH 2 , and CH 2 at three bond lengths have been calculated with the second multireference perturbation theory. The dissociation behaviors of CH 4 and HF have also been investigated. Comparisons with other approximate theoretical models as well as the experimental data have been carried out to show their relative performances. © 2013 Wiley Periodicals, Inc.