6533b7d0fe1ef96bd125b7a5
RESEARCH PRODUCT
Communication: The performance of non-iterative coupled cluster quadruples models
Devin A. MatthewsJürgen GaussJanus J. EriksenPoul Jørgensensubject
Physicssymbols.namesakeCoupled clusterNumerical analysisQuantum mechanicsExcited statesymbolsGeneral Physics and AstronomyApplied mathematicsPhysical and Theoretical ChemistryLagrangiandescription
We compare the numerical performance of various non-iterative coupled cluster (CC) quadruples models. The results collectively show how approaches that attempt to correct the CC singles and doubles energy for the combined effect of triple and quadruple excitations all fail at recovering the correlation energy of the full CC singles, doubles, triples, and quadruples (CCSDTQ) model to within sufficient accuracy. Such a level of accuracy is only achieved by models that make corrections to the full CC singles, doubles, and triples (CCSDT) energy for the isolated effect of quadruple excitations of which the CCSDT(Q–3) and CCSDT(Q–4) models of the Lagrangian-based CCSDT(Q–n) perturbation series are found to outperform alternative models that add either of the established [Q] and (Q) corrections to the CCSDT energy.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-07-22 |