Orbitaloptimized density cumulant functional theory
Abstract
In density cumulant functional theory (DCFT) the electronic energy is evaluated from the oneparticle density matrix and twoparticle density cumulant, circumventing the computation of the wavefunction. To achieve this, the oneparticle density matrix is decomposed exactly into the meanfield (idempotent) and correlation components. While the latter can be entirely derived from the density cumulant, the former must be obtained by choosing a specific set of orbitals. In the original DCFT formulation [W. Kutzelnigg, J. Chem. Phys. 125, 171101 (2006)] the orbitals were determined by diagonalizing the effective Fock operator, which introduces partial orbital relaxation. Here we present a new orbitaloptimized formulation of DCFT where the energy is variationally minimized with respect to orbital rotations. This introduces important energy contributions and significantly improves the description of the dynamic correlation. In addition, it greatly simplifies the computation of analytic gradients, for which expressions are also presented. We offer a perturbative analysis of the new orbital stationarity conditions and benchmark their performance for a variety of chemical systems.
 Authors:
 Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602 (United States)
 Publication Date:
 OSTI Identifier:
 22251325
 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:
 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 97 MATHEMATICAL METHODS AND COMPUTING; DENSITY; DENSITY MATRIX; PARTICLES; RELAXATION; WAVE FUNCTIONS
Citation Formats
Sokolov, Alexander Yu., Email: asokolov@uga.edu, and Schaefer, Henry F. Orbitaloptimized density cumulant functional theory. United States: N. p., 2013.
Web. doi:10.1063/1.4833138.
Sokolov, Alexander Yu., Email: asokolov@uga.edu, & Schaefer, Henry F. Orbitaloptimized density cumulant functional theory. United States. doi:10.1063/1.4833138.
Sokolov, Alexander Yu., Email: asokolov@uga.edu, and Schaefer, Henry F. Thu .
"Orbitaloptimized density cumulant functional theory". United States.
doi:10.1063/1.4833138.
@article{osti_22251325,
title = {Orbitaloptimized density cumulant functional theory},
author = {Sokolov, Alexander Yu., Email: asokolov@uga.edu and Schaefer, Henry F.},
abstractNote = {In density cumulant functional theory (DCFT) the electronic energy is evaluated from the oneparticle density matrix and twoparticle density cumulant, circumventing the computation of the wavefunction. To achieve this, the oneparticle density matrix is decomposed exactly into the meanfield (idempotent) and correlation components. While the latter can be entirely derived from the density cumulant, the former must be obtained by choosing a specific set of orbitals. In the original DCFT formulation [W. Kutzelnigg, J. Chem. Phys. 125, 171101 (2006)] the orbitals were determined by diagonalizing the effective Fock operator, which introduces partial orbital relaxation. Here we present a new orbitaloptimized formulation of DCFT where the energy is variationally minimized with respect to orbital rotations. This introduces important energy contributions and significantly improves the description of the dynamic correlation. In addition, it greatly simplifies the computation of analytic gradients, for which expressions are also presented. We offer a perturbative analysis of the new orbital stationarity conditions and benchmark their performance for a variety of chemical systems.},
doi = {10.1063/1.4833138},
journal = {Journal of Chemical Physics},
number = 20,
volume = 139,
place = {United States},
year = {Thu Nov 28 00:00:00 EST 2013},
month = {Thu Nov 28 00:00:00 EST 2013}
}

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