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dc.contributor.authorBochevarov, Arteum D.en_US
dc.contributor.authorSherrill, C. Daviden_US
dc.date.accessioned2013-04-04T20:16:36Z
dc.date.available2013-04-04T20:16:36Z
dc.date.issued2005-06
dc.identifier.citationBochevarov, Arteum D. and Sherrill, C. David, "Hybrid correlation models based on active-space partitioning: Correcting second-order Møller-Plesset perturbation theory for bond-breaking reactions," Journal of Chemical Physics, 122, 23, (June 15 2005)en_US
dc.identifier.issn0021-9606
dc.identifier.urihttp://hdl.handle.net/1853/46637
dc.description© 2005 American Institute of Physics. The electronic version of this article is the complete one and can be found at: http://dx.doi.org/10.1063/1.1935508en_US
dc.descriptionDOI: 10.1063/1.1935508en_US
dc.description.abstractMøller–Plesset second-order (MP2) perturbation theory breaks down at molecular geometries which are far away from equilibrium. We decompose the MP2 energy into contributions from different orbital subspaces and show that the divergent behavior of the MP2 energy comes from the excitations located within a small (or sometimes even the minimal) active space. The divergent behavior of the MP2 energy at large interfragment distances may be corrected by replacing a small number of terms by their more robust counterparts from coupled-cluster (CCSD) theory. We investigated several schemes of such a substitution, and we find that a coupling between the active-space CCSD and the remaining MP2 amplitudes is necessary to obtain the best results. This naturally leads us to an approach which has previously been examined in the context of cost-saving approximations to CCSD for equilibrium properties by Nooijen [ J. Chem. Phys. 111, 10815 (1999) ]. The hybrid MP2–CCSD approach, which has the same formal scaling as conventional MP2 theory, provides potential curves with a correct shape for bond-breaking reactions of BH, CH₄, and HF. The error of the MP2–CCSD method (measured against full configuration-interaction data) is smaller than that of MP2 at all interfragment separations and is qualitatively similar to that of full CCSD.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectBoron compoundsen_US
dc.subjectOrganic compoundsen_US
dc.subjectHydrogen compoundsen_US
dc.subjectPerturbation theoryen_US
dc.subjectCoupled cluster calculationsen_US
dc.subjectChemical bondsen_US
dc.subjectReaction kinetics theoryen_US
dc.subjectMolecular configurationsen_US
dc.titleHybrid correlation models based on active-space partitioning: Correcting second-order Møller-Plesset perturbation theory for bond-breaking reactionsen_US
dc.typeArticleen_US
dc.contributor.corporatenameGeorgia Institute of Technology. Center for Organic Photonics and Electronicsen_US
dc.contributor.corporatenameGeorgia Institute of Technology. Center for Computational Molecular Science and Technologyen_US
dc.contributor.corporatenameGeorgia Institute of Technology. School of Chemistry and Biochemistryen_US
dc.publisher.originalAmerican Institute of Physicsen_US
dc.identifier.doi10.1063/1.1935508


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