Coupled cluster channels in the homogeneous electron gas

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dc.citation.articleNumber124102en_US
dc.citation.issueNumber12en_US
dc.citation.journalTitleThe Journal of Chemical Physicsen_US
dc.citation.volumeNumber140en_US
dc.contributor.authorShepherd, James J.en_US
dc.contributor.authorHenderson, Thomas M.en_US
dc.contributor.authorScuseria, Gustavo E.en_US
dc.date.accessioned2017-05-24T16:33:35Zen_US
dc.date.available2017-05-24T16:33:35Zen_US
dc.date.issued2014en_US
dc.description.abstractWe discuss diagrammatic modifications to the coupled cluster doubles (CCD) equations, wherein different groups of terms out of rings, ladders, crossed-rings, and mosaics can be removed to form approximations to the coupled cluster method, of interest due to their similarity with various types of random phase approximations. The finite uniform electron gas (UEG) is benchmarked for 14- and 54-electron systems at the complete basis set limit over a wide density range and performance of different flavours of CCD is determined. These results confirm that rings generally overcorrelate and ladders generally undercorrelate; mosaics-only CCD yields a result surprisingly close to CCD. We use a recently developed numerical analysis [J. J. Shepherd and A. Grüneis, Phys. Rev. Lett. 110, 226401 (2013)] to study the behaviours of these methods in the thermodynamic limit. We determine that the mosaics, on forming the Brueckner one-body Hamiltonian, open a gap in the effective one-particle eigenvalues at the Fermi energy. Numerical evidence is presented which shows that methods based on this renormalisation have convergent energies in the thermodynamic limit including mosaic-only CCD, which is just a renormalised MP2. All other methods including only a single channel, namely, ladder-only CCD, ring-only CCD, and crossed-ring-only CCD, appear to yield divergent energies; incorporation of mosaic terms prevents this from happening.en_US
dc.identifier.citationShepherd, James J., Henderson, Thomas M. and Scuseria, Gustavo E.. "Coupled cluster channels in the homogeneous electron gas." <i>The Journal of Chemical Physics,</i> 140, no. 12 (2014) AIP Publishing: http://dx.doi.org/10.1063/1.4867783.en_US
dc.identifier.doihttp://dx.doi.org/10.1063/1.4867783en_US
dc.identifier.urihttps://hdl.handle.net/1911/94376en_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.titleCoupled cluster channels in the homogeneous electron gasen_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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