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Title: Multi-component symmetry-projected approach for molecular ground state correlations

The symmetry-projected Hartree–Fock ansatz for the electronic structure problem can efficiently account for static correlation in molecules, yet it is often unable to describe dynamic correlation in a balanced manner. Here, we consider a multi-component, systematically improvable approach, that accounts for all ground state correlations. Our approach is based on linear combinations of symmetry-projected configurations built out of a set of non-orthogonal, variationally optimized determinants. The resulting wavefunction preserves the symmetries of the original Hamiltonian even though it is written as a superposition of deformed (broken-symmetry) determinants. We show how short expansions of this kind can provide a very accurate description of the electronic structure of simple chemical systems such as the nitrogen and the water molecules, along the entire dissociation profile. In addition, we apply this multi-component symmetry-projected approach to provide an accurate interconversion profile among the peroxo and bis(μ-oxo) forms of [Cu{sub 2}O{sub 2}]{sup 2+}, comparable to other state-of-the-art quantum chemical methods.
Authors:
 [1] ; ;  [1] ;  [2]
  1. Department of Chemistry, Rice University, Houston, Texas 77005 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22251363
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER OXIDES; DISSOCIATION; ELECTRONIC STRUCTURE; GROUND STATES; HAMILTONIANS; SYMMETRY BREAKING; WAVE FUNCTIONS