Accurate ab initio potential energy curve of F-2. I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method

TitleAccurate ab initio potential energy curve of F-2. I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method
Publication TypeJournal Article
Year of Publication2007
AuthorsBytautas L, Nagata T, Gordon MS, Ruedenberg K
Journal TitleJournal of Chemical Physics
Volume127
Pages164317
Date PublishedOct
Type of ArticleReview
ISBN Number0021-9606
Accession NumberISI:000250589400038
Keywordsbasis-set convergence, BOND-BREAKING, coupled-cluster theory, ELECTRON-PAIR APPROXIMATION, MATRIX, minimal basis-sets, MULTIREFERENCE, perturbation-theory, RENORMALIZATION-GROUP, self-consistent-field, TRANSITION-STATE, wave-functions
Abstract

The recently introduced method of correlation energy extrapolation by intrinsic scaling (CEEIS) is used to calculate the nonrelativistic electron correlations in the valence shell of the F-2 molecule at 13 internuclear distances along the ground state potential energy curve from 1.14 A to 8 A, the equilibrium distance being 1.412 A. Using Dunning's correlation-consistent double-, triple-, and quadruple-zeta basis sets, the full configuration interaction energies are determined, with an accuracy of about 0.3 mhartree, by successively generating up to octuple excitations with respect to multiconfigurational reference functions that strongly change along the reaction path. The energies of the reference functions and those of the correlation energies with respect to these reference functions are then extrapolated to their complete basis set limits. The applicability of the CEEIS method to strongly multiconfigurational reference functions is documented in detail.

DOI10.1063/1.2800017
Alternate JournalJ. Chem. Phys.