On the contribution of higher-order excitations to correlation energies: The ground state of the water molecule |
| |
Authors: | Stephen Wilson David M Silver |
| |
Institution: | (1) Science Research Council, Daresbury Laboratory, WA4 4AD Daresbury, Warrington, England;(2) Applied Physics Laboratory, The Johns Hopkins University, 20810 Laurel, Maryland, USA |
| |
Abstract: | Using the results of a configuration interaction calculation reported by Rosenberg and Shavitt, we derive an approximation
to the correlation energy which may be associated with the sum to infinite order of all linked diagrams involving singly-
and doubly-excited states. This result is compared with that obtained by calculation of the energy through third-order. The
fourth-order linked diagrams involving quadruply-excited states are computed. It is shown that there is a considerable degree
of cancellation between the fourth-order linked diagram energy terms involving doubly-excited intermediate states only and
those which contain quadruply-excited states. |
| |
Keywords: | Higher-order excitations contribution of ∼ to correlation energies Water molecule |
本文献已被 SpringerLink 等数据库收录! |