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Density fitting for three-electron integrals in explicitly correlated electronic structure theory

Density fitting for three-electron integrals in explicitly correlated electronic structure theory
Density fitting for three-electron integrals in explicitly correlated electronic structure theory
The principal challenge in using explicitly correlated wavefunctions for molecules is the evaluation of nonfactorizable integrals over the coordinates of three or more electrons. Immense progress was made in tackling this problem through the introduction of a single-particle resolution of the identity. Decompositions of sufficient accuracy can be achieved, but only with large auxiliary basis sets. Density fitting is an alternative integral approximation scheme, which has proven to be very reliable for two-electron integrals. Here, we extend density fitting to the treatment of all three-electron integrals that appear at the MP2-F12/3*A level of theory. We demonstrate that the convergence of energies with respect to auxiliary basis size is much more rapid with density fitting than with the traditional resolution-of-the-identity approach.
0021-9606
1-12
Womack, James C.
ef9e1954-4a38-4e89-bf25-741a0738e85b
Manby, Frederick R.
0a76e08a-3468-49ca-8826-45225c00ade0
Womack, James C.
ef9e1954-4a38-4e89-bf25-741a0738e85b
Manby, Frederick R.
0a76e08a-3468-49ca-8826-45225c00ade0

Womack, James C. and Manby, Frederick R. (2014) Density fitting for three-electron integrals in explicitly correlated electronic structure theory. The Journal of Chemical Physics, 140 (4), 1-12. (doi:10.1063/1.4863136).

Record type: Article

Abstract

The principal challenge in using explicitly correlated wavefunctions for molecules is the evaluation of nonfactorizable integrals over the coordinates of three or more electrons. Immense progress was made in tackling this problem through the introduction of a single-particle resolution of the identity. Decompositions of sufficient accuracy can be achieved, but only with large auxiliary basis sets. Density fitting is an alternative integral approximation scheme, which has proven to be very reliable for two-electron integrals. Here, we extend density fitting to the treatment of all three-electron integrals that appear at the MP2-F12/3*A level of theory. We demonstrate that the convergence of energies with respect to auxiliary basis size is much more rapid with density fitting than with the traditional resolution-of-the-identity approach.

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Submitted date: 27 November 2013
Accepted/In Press date: 10 January 2014
e-pub ahead of print date: 31 January 2014
Published date: January 2014
Organisations: Computational Systems Chemistry

Identifiers

Local EPrints ID: 403905
URI: http://eprints.soton.ac.uk/id/eprint/403905
ISSN: 0021-9606
PURE UUID: 0e38f66f-4810-4c82-9be0-92772c15a713
ORCID for James C. Womack: ORCID iD orcid.org/0000-0001-5497-4482

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Date deposited: 16 Dec 2016 09:45
Last modified: 02 Dec 2019 19:47

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Contributors

Author: James C. Womack ORCID iD
Author: Frederick R. Manby

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