Garza, Alejandro J.Bulik, Ireneusz W.Henderson, Thomas M.Scuseria, Gustavo E.2015-02-272015-02-272015Garza, Alejandro J., Bulik, Ireneusz W., Henderson, Thomas M., et al.. "Synergy between pair coupled cluster doubles and pair density functional theory." <i>The Journal of Chemical Physics,</i> 142, (2015) AIP Publishing: 44109. http://dx.doi.org/10.1063/1.4906607.https://hdl.handle.net/1911/79046Pair coupled cluster doubles (pCCD) has been recently studied as a method capable of accounting for static correlation with low polynomial cost. We present three combinations of pCCD with Kohn–Sham functionals of the density and on-top pair density (the probability of finding two electrons on top of each other) to add dynamic correlation to pCCD without double counting. With a negligible increase in computational cost, these pCCD+DFT blends greatly improve upon pCCD in the description of typical problems where static and dynamic correlations are both important. We argue that—as a black-box method with low scaling, size-extensivity, size-consistency, and a simple quasidiagonal two-particle density matrix—pCCD is an excellent match for pair density functionals in this type of fusion of multireference wavefunctions with DFT.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by AIP Publishing LLC.Journal articlehttp://dx.doi.org/10.1063/1.4906607