A cumulant functional for static and dynamic correlation

作者：Hollett Joshua W; Hosseini Hessam; Menzies Cameron

来源：Journal of Chemical Physics, 2016, 145(8): 084106.

DOI：10.1063/1.4961243

A functional for the cumulant energy is introduced. The functional is composed of a pair-correction and static and dynamic correlation energy components. The pair-correction and static correlation energies are functionals of the natural orbitals and the occupancy transferred between near-degenerate orbital pairs, rather than the orbital occupancies themselves. The dynamic correlation energy is a functional of the statically correlated on-top two-electron density. The on-top density functional used in this study is the well-known Colle-Salvetti functional. Using the cc-pVTZ basis set, the functional effectively models the bond dissociation of H-2, LiH, and N-2 with equilibrium bond lengths and dissociation energies comparable to those provided by multireference second-order perturbation theory. The performance of the cumulant functional is less impressive for HF and F-2, mainly due to an underestimation of the dynamic correlation energy by the Colle-Salvetti functional. Published by AIP Publishing.

• 出版日期2016-8-28