Seniority zero pair coupled cluster doubles theory

dc.citation.articleNumber214113en_US
dc.citation.issueNumber21en_US
dc.citation.journalTitleThe Journal of Chemical Physicsen_US
dc.citation.volumeNumber140en_US
dc.contributor.authorStein, Tamaren_US
dc.contributor.authorHenderson, Thomas M.en_US
dc.contributor.authorScuseria, Gustavo E.en_US
dc.date.accessioned2017-05-24T16:33:36Zen_US
dc.date.available2017-05-24T16:33:36Zen_US
dc.date.issued2014en_US
dc.description.abstractCoupled clusterᅠtheoryᅠwith single and doubleᅠexcitationsᅠaccurately describes weak electronᅠcorrelationᅠbut is known to fail in cases of strong staticᅠcorrelation.ᅠFascinatingly, however, pairᅠcoupled clusterᅠdoubles (p-CCD), a simplified version of theᅠtheoryᅠlimited to pairᅠexcitationsᅠthat preserve the seniority of the reference determinant (i.e.,ᅠthe number of unpaired electrons), hasᅠmean fieldᅠcomputational cost and is an excellent approximation to the full configuration interaction (FCI) of the paired space provided that the orbital basis defining the pairing scheme is adequately optimized. In previous work, we have shown that optimization of the pairing scheme in the seniority zero FCI leads to a very accurate description of staticᅠcorrelation.ᅠThe same conclusion extends to p-CCD if the orbitals are optimized to make the p-CCD energy stationary. We here demonstrate these results with numerous examples. We also explore the contributions of different seniority sectors to theᅠcoupled clusterᅠdoublesᅠ(CCD)ᅠcorrelationᅠenergy using different orbital bases. We consider both Hartree-Fock and Brueckner orbitals, and the role of orbital localization. We show how one can pair the orbitals so that the role of the Brueckner orbitals at theᅠCCDᅠlevel is retained at the p-CCD level. Moreover, we explore ways of extendingᅠCCDᅠto accurately describe strongly correlated systems.en_US
dc.identifier.citationStein, Tamar, Henderson, Thomas M. and Scuseria, Gustavo E.. "Seniority zero pair coupled cluster doubles theory." <i>The Journal of Chemical Physics,</i> 140, no. 21 (2014) AIP Publishing: http://dx.doi.org/10.1063/1.4880819.en_US
dc.identifier.doihttp://dx.doi.org/10.1063/1.4880819en_US
dc.identifier.urihttps://hdl.handle.net/1911/94381en_US
dc.language.isoengen_US
dc.publisherAIP Publishingen_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.titleSeniority zero pair coupled cluster doubles theoryen_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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