Spin-Free [2]R12 Basis Set Incompleteness Correction to the Local Multireference Configuration Interaction and the Local Multireference Average Coupled Pair Functional Methods

Luke B Roskop; Edward F Valeev; Emily A Carter; Mark S Gordon; Theresa L Windus

doi:10.1021/acs.jctc.6b00315

Spin-Free [2]R12 Basis Set Incompleteness Correction to the Local Multireference Configuration Interaction and the Local Multireference Average Coupled Pair Functional Methods

J Chem Theory Comput. 2016 Jul 12;12(7):3176-84. doi: 10.1021/acs.jctc.6b00315. Epub 2016 Jun 28.

Authors

Luke B Roskop¹, Edward F Valeev², Emily A Carter³, Mark S Gordon¹, Theresa L Windus¹

Affiliations

¹ Department of Chemistry, Iowa State University , Ames, Iowa 50010, United States.
² Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
³ Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics, and Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.

PMID: 27281508
DOI: 10.1021/acs.jctc.6b00315

Abstract

The local multireference configuration interaction (LMRCI) and local multireference averaged coupled pair functional (LMRACPF) methods are extended to include explicit correlation via the universal spin-free [2]R12 basis set incompleteness correction. Four test cases are examined to measure the performance of the LMRCI+[2]R12 (without and with the Davidson + Q correction for size-extensivity) and LMRACPF+[2]R12 methods. These tests examine bond dissociation energies (BDEs) for ethene, perfluoroethene, propene, and 2-butene. As has been demonstrated for other methods, the LMRCI+[2]R12/LMRCI+Q+[2]R12/LMRACPF+[2]R12 BDEs are as accurate as the conventional LMRCI/LMRACPF BDEs that are computed with the basis set one cardinal number higher. It is shown that LMRCI+[2]R12/LMRCI+Q+[2]R12/LMRACPF+[2]R12 BDEs computed with the June calendar basis sets preserve the accuracy of the corresponding BDEs computed with the conventional aug-cc-pVXZ basis sets (where X = D, T, Q).