Variational configuration interaction methods and comparison with perturbation theory
Article first published online: 18 JUN 2009
Copyright © 1977 John Wiley & Sons, Inc.
International Journal of Quantum Chemistry
Supplement: Proceedings of the International Symposium on Atomic, Molecular, and Solid-state Theory, Collision Phenomena, and Computational Methods
Volume 12, Issue Supplement S11, pages 149–163, 16/22 January 1977
How to Cite
Pople, J. A., Seeger, R. and Krishnan, R. (1977), Variational configuration interaction methods and comparison with perturbation theory. Int. J. Quantum Chem., 12: 149–163. doi: 10.1002/qua.560120820
- Issue published online: 18 JUN 2009
- Article first published online: 18 JUN 2009
- Manuscript Received: 31 JAN 1977
- National Science Foundation. Grant Number: CHE75-09808
A configuration interaction (Cl) procedure which includes all single and double substitutions from an unrestricted Hartree-Fock single determinant is described. This has the feature that Møller-Plesset perturbation results to second and third order are obtained in the first Cl iterative cycle. The procedure also avoids the necessity of a full two-electron integral transformation. A simple expression for correcting the final Cl energy for lack of size consistency is proposed. Finally, calculations on a series of small molecules are presented to compare these Cl methods with perturbation theory.