A new size extensive multireference perturbation theory
Article first published online: 7 NOV 2013
Copyright © 2013 Wiley Periodicals, Inc.
Journal of Computational Chemistry
Volume 35, Issue 2, pages 121–129, 15 January 2014
How to Cite
How to cite this article: J. Comput. Chem. 2014, 35, 121-129. DOI: 10.1002/jcc.23471, .
- Issue published online: 8 DEC 2013
- Article first published online: 7 NOV 2013
- Manuscript Accepted: 6 OCT 2013
- Manuscript Revised: 3 SEP 2013
- Manuscript Received: 2 MAR 2013
- National Natural Science foundation of China . Grant Number: 21173020
- multireference perturbation theory;
- single reference perturbation theory;
- Rayleigh-Schrödinger perturbation theory;
- Møller–Plesset perturbation theory;
- size extensivity;
- orbital invariance
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 H2 and BH monomers. Spectroscopic constants of as well as the ground state energies of H2O, NH2, and CH2 at three bond lengths have been calculated with the second multireference perturbation theory. The dissociation behaviors of CH4 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.