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Title: Projected Hartree-Fock theory as a polynomial of particle-hole excitations and its combination with variational coupled cluster theory

Projected Hartree-Fock theory provides an accurate description of many kinds of strong correlations but does not properly describe weakly correlated systems. Coupled cluster theory, in contrast, does the opposite. It therefore seems natural to combine the two so as to describe both strong and weak correlations with high accuracy in a relatively black-box manner. Combining the two approaches, however, is made more difficult by the fact that the two techniques are formulated very differently. In earlier work, we showed how to write spin-projected Hartree-Fock in a coupled-cluster-like language. Here in this work, we fill in the gaps in that earlier work. Further, we combine projected Hartree-Fock and coupled cluster theory in a variational formulation and show how the combination performs for the description of the Hubbard Hamiltonian and for several small molecular systems.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [2]
  1. Rice Univ., Houston, TX (United States). Department of Chemistry
  2. Rice Univ., Houston, TX (United States). Department of Chemistry and Department of Physics and Astronomy
Publication Date:
Grant/Contract Number:
SC0012575; FG02-09ER16053
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 146; Journal Issue: 18; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Rice Univ., Houston, TX (United States). Department of Chemistry
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1465952
Alternate Identifier(s):
OSTI ID: 1361873