Correlation energy extrapolation by many-body expansion

Boschen, Jeffery S.; Theis, Daniel; Ruedenberg, Klaus; Windus, Theresa L.

doi:10.1021/acs.jpca.6b10953

Title: Correlation energy extrapolation by many-body expansion

Abstract

Accounting for electron correlation is required for high accuracy calculations of molecular energies. The full configuration interaction (CI) approach can fully capture the electron correlation within a given basis, but it does so at a computational expense that is impractical for all but the smallest chemical systems. In this work, a new methodology is presented to approximate configuration interaction calculations at a reduced computational expense and memory requirement, namely, the correlation energy extrapolation by many-body expansion (CEEMBE). This method combines a MBE approximation of the CI energy with an extrapolated correction obtained from CI calculations using subsets of the virtual orbitals. The extrapolation approach is inspired by, and analogous to, the method of correlation energy extrapolation by intrinsic scaling. Benchmark calculations of the new method are performed on diatomic fluorine and ozone. Finally, the method consistently achieves agreement with CI calculations to within a few mhartree and often achieves agreement to within ~1 millihartree or less, while requiring significantly less computational resources.

Authors:

Boschen, Jeffery S. ^[1]; Theis, Daniel ^[1]; Ruedenberg, Klaus ^[1]; Windus, Theresa L. ^[1]

Ames Lab. and Iowa State Univ., Ames, IA (United States)

Publication Date:: Mon Jan 09 00:00:00 EST 2017

Research Org.:: Ames Lab., Ames, IA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1347403

Report Number(s):: IS-J-9215
Journal ID: ISSN 1089-5639

Grant/Contract Number:: AC02-07CH11358

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Additional Journal Information:: Journal Volume: 121; Journal Issue: 4; Journal ID: ISSN 1089-5639

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats


                    Boschen, Jeffery S., Theis, Daniel, Ruedenberg, Klaus, and Windus, Theresa L. Correlation energy extrapolation by many-body expansion.  United States: N. p., 2017. 
Web.  doi:10.1021/acs.jpca.6b10953.

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                    Boschen, Jeffery S., Theis, Daniel, Ruedenberg, Klaus, & Windus, Theresa L. Correlation energy extrapolation by many-body expansion.  United States.  https://doi.org/10.1021/acs.jpca.6b10953

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                    Boschen, Jeffery S., Theis, Daniel, Ruedenberg, Klaus, and Windus, Theresa L. Mon .  
"Correlation energy extrapolation by many-body expansion".  United States.  https://doi.org/10.1021/acs.jpca.6b10953.  https://www.osti.gov/servlets/purl/1347403.

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@article{osti_1347403,

  title        = {Correlation energy extrapolation by many-body expansion},

  author       = {Boschen, Jeffery S. and Theis, Daniel and Ruedenberg, Klaus and Windus, Theresa L.},

  abstractNote = {Accounting for electron correlation is required for high accuracy calculations of molecular energies. The full configuration interaction (CI) approach can fully capture the electron correlation within a given basis, but it does so at a computational expense that is impractical for all but the smallest chemical systems. In this work, a new methodology is presented to approximate configuration interaction calculations at a reduced computational expense and memory requirement, namely, the correlation energy extrapolation by many-body expansion (CEEMBE). This method combines a MBE approximation of the CI energy with an extrapolated correction obtained from CI calculations using subsets of the virtual orbitals. The extrapolation approach is inspired by, and analogous to, the method of correlation energy extrapolation by intrinsic scaling. Benchmark calculations of the new method are performed on diatomic fluorine and ozone. Finally, the method consistently achieves agreement with CI calculations to within a few mhartree and often achieves agreement to within ~1 millihartree or less, while requiring significantly less computational resources.},

  doi          = {10.1021/acs.jpca.6b10953},

  journal      = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},

  number       = 4,

  volume       = 121,

  place        = {United States},

  year         = {Mon Jan 09 00:00:00 EST 2017},

  month        = {Mon Jan 09 00:00:00 EST 2017}

}

Copy to clipboard

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Works referenced in this record:

A priori identification of configurational deadwood
journal, February 2009

Bytautas, Laimutis; Ruedenberg, Klaus
Chemical Physics, Vol. 356, Issue 1-3
DOI: 10.1016/j.chemphys.2008.11.021

Fermion Monte Carlo without fixed nodes: A game of life, death, and annihilation in Slater determinant space
journal, January 2009

Booth, George H.; Thom, Alex J. W.; Alavi, Ali
The Journal of Chemical Physics, Vol. 131, Issue 5
DOI: 10.1063/1.3193710

A deterministic alternative to the full configuration interaction quantum Monte Carlo method
journal, July 2016

Tubman, Norm M.; Lee, Joonho; Takeshita, Tyler Y.
The Journal of Chemical Physics, Vol. 145, Issue 4
DOI: 10.1063/1.4955109

Communication: An adaptive configuration interaction approach for strongly correlated electrons with tunable accuracy
journal, April 2016

Schriber, Jeffrey B.; Evangelista, Francesco A.
The Journal of Chemical Physics, Vol. 144, Issue 16
DOI: 10.1063/1.4948308

Compressive sampling in configuration interaction wavefunctions
journal, January 2015

Knowles, Peter J.
Molecular Physics, Vol. 113, Issue 13-14
DOI: 10.1080/00268976.2014.1003621

Seniority number description of potential energy surfaces: Symmetric dissociation of water, N ₂ , C ₂ , and Be ₂
journal, September 2015

Bytautas, Laimutis; Scuseria, Gustavo E.; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 143, Issue 9
DOI: 10.1063/1.4929904

iCI: Iterative CI toward full CI
journal, January 2016

Liu, Wenjian; Hoffmann, Mark R.
Journal of Chemical Theory and Computation, Vol. 12, Issue 3
DOI: 10.1021/acs.jctc.5b01099

Fixed-node diffusion Monte Carlo potential energy curve of the fluorine molecule F ₂ using selected configuration interaction trial wavefunctions
journal, January 2015

Giner, Emmanuel; Scemama, Anthony; Caffarel, Michel
The Journal of Chemical Physics, Vol. 142, Issue 4
DOI: 10.1063/1.4905528

Correlation energy extrapolation by intrinsic scaling. I. Method and application to the neon atom
journal, January 2004

Bytautas, Laimutis; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 121, Issue 22
DOI: 10.1063/1.1811603

Correlation energy extrapolation by intrinsic scaling. II. The water and the nitrogen molecule
journal, January 2004

Bytautas, Laimutis; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 121, Issue 22
DOI: 10.1063/1.1811604

Correlation energy extrapolation by intrinsic scaling. IV. Accurate binding energies of the homonuclear diatomic molecules carbon, nitrogen, oxygen, and fluorine
journal, April 2005

Bytautas, Laimutis; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 122, Issue 15
DOI: 10.1063/1.1869493

Fragmentation Methods: A Route to Accurate Calculations on Large Systems
journal, August 2011

Gordon, Mark S.; Fedorov, Dmitri G.; Pruitt, Spencer R.
Chemical Reviews, Vol. 112, Issue 1
DOI: 10.1021/cr200093j

Aiming for Benchmark Accuracy with the Many-Body Expansion
journal, June 2014

Richard, Ryan M.; Lao, Ka Un; Herbert, John M.
Accounts of Chemical Research, Vol. 47, Issue 9
DOI: 10.1021/ar500119q

Energy-Based Molecular Fragmentation Methods
journal, April 2015

Collins, Michael A.; Bettens, Ryan P. A.
Chemical Reviews, Vol. 115, Issue 12
DOI: 10.1021/cr500455b

The method of increments—a wavefunction-based ab initio correlation method for solids
journal, May 2006

Paulus, B.
Physics Reports, Vol. 428, Issue 1
DOI: 10.1016/j.physrep.2006.01.003

Accurate ab initio potential energy curve of F2. I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method
journal, October 2007

Bytautas, Laimutis; Nagata, Takeshi; Gordon, Mark S.
The Journal of Chemical Physics, Vol. 127, Issue 16
DOI: 10.1063/1.2800017

Accurate ab initio potential energy curve of O2. I. Nonrelativistic full configuration interaction valence correlation by the correlation energy extrapolation by intrinsic scaling method
journal, February 2010

Bytautas, Laimutis; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 132, Issue 7
DOI: 10.1063/1.3298373

Accurate Potential Energy Curve for B ₂ . Ab Initio Elucidation of the Experimentally Elusive Ground State Rotation-Vibration Spectrum
journal, February 2012

Bytautas, Laimutis; Matsunaga, Nikita; Scuseria, Gustavo E.
The Journal of Physical Chemistry A, Vol. 116, Issue 7
DOI: 10.1021/jp210473e

Accurate ab initio potential energy curves and spectroscopic properties of the four lowest singlet states of C2
journal, December 2013

Boschen, Jeffery S.; Theis, Daniel; Ruedenberg, Klaus
Theoretical Chemistry Accounts, Vol. 133, Issue 2
DOI: 10.1007/s00214-013-1425-x

Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen
journal, January 1989

Dunning, Thom H.
The Journal of Chemical Physics, Vol. 90, Issue 2
DOI: 10.1063/1.456153

Direct configuration interaction and multiconfigurational self-consistent-field method for multiple active spaces with variable occupations. I. Method
journal, November 2003

Ivanic, Joseph
The Journal of Chemical Physics, Vol. 119, Issue 18
DOI: 10.1063/1.1615954

General atomic and molecular electronic structure system
journal, November 1993

Schmidt, Michael W.; Baldridge, Kim K.; Boatz, Jerry A.
Journal of Computational Chemistry, Vol. 14, Issue 11, p. 1347-1363
DOI: 10.1002/jcc.540141112

An intersection seam between the ground state of ozone and an excited state of like symmetry ^a)
journal, November 1990

Xantheas, S.; Elbert, S. T.; Ruedenberg, K.
The Journal of Chemical Physics, Vol. 93, Issue 10
DOI: 10.1063/1.459379

Potential energy surfaces of ozone. I
journal, June 1991

Xantheas, Sotiris S.; Atchity, Gregory J.; Elbert, Stephen T.
The Journal of Chemical Physics, Vol. 94, Issue 12
DOI: 10.1063/1.460140

Strong shifts in diabatic nondynamic electron correlations cause conical intersection between low‐lying closed‐shell adiabatic singlets of like symmetry in ozone
journal, September 1993

Atchity, Gregory J.; Ruedenberg, Klaus
The Journal of Chemical Physics, Vol. 99, Issue 5
DOI: 10.1063/1.466229

Global potential energy surfaces for the lowest two 1 A ′ states of ozone
journal, August 1997

Atchity, G. J.; Ruedenberg, K.
Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta), Vol. 96, Issue 3
DOI: 10.1007/s002140050220

The intersection seam between the 1 1 A ′ and 2 1 A ′ states of ozone
journal, August 1997

Atchity, G. J.; Ruedenberg, K.; Nanayakkara, A.
Theoretical Chemistry Accounts: Theory, Computation, and Modeling (Theoretica Chimica Acta), Vol. 96, Issue 3
DOI: 10.1007/s002140050221

Theoretical results for the excited states of ozone
journal, May 1972

Hay, P. J.; Goodard, W. A.
Chemical Physics Letters, Vol. 14, Issue 1
DOI: 10.1016/0009-2614(72)87137-9

Theoretical evidence for bound electronic excited states of ozone
journal, December 1973

Hay, P. Jeffrey; Dunning, Thom H.; Goddard, William A.
Chemical Physics Letters, Vol. 23, Issue 4
DOI: 10.1016/0009-2614(73)89001-3

Theoretical Evidence for a Stable form of Cyclic Ozone, and its Chemical Consequences
journal, January 1973

Wright, James S.
Canadian Journal of Chemistry, Vol. 51, Issue 1
DOI: 10.1139/v73-020

Theoretical investigation of the cyclic conformer of ozone
journal, October 1974

Shih, Shingkuo; Buenker, Robert J.; Peyerimhoff, Sigrid D.
Chemical Physics Letters, Vol. 28, Issue 4
DOI: 10.1016/0009-2614(74)80080-1

The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study
journal, March 2016

Theis, Daniel; Ivanic, Joseph; Windus, Theresa L.
The Journal of Chemical Physics, Vol. 144, Issue 10
DOI: 10.1063/1.4942019

Works referencing / citing this record:

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The Journal of Chemical Physics, Vol. 151, Issue 17
DOI: 10.1063/1.5126216

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journal, May 2019

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International Journal of Quantum Chemistry, Vol. 119, Issue 19
DOI: 10.1002/qua.25968

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journal, June 2019

Zimmerman, Paul M.; Rask, Alan E.
The Journal of Chemical Physics, Vol. 150, Issue 24
DOI: 10.1063/1.5100934

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Title: Correlation energy extrapolation by many-body expansion

Abstract

Citation Formats

A priori identification of configurational deadwood journal, February 2009

Fermion Monte Carlo without fixed nodes: A game of life, death, and annihilation in Slater determinant space journal, January 2009

A deterministic alternative to the full configuration interaction quantum Monte Carlo method journal, July 2016

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Seniority number description of potential energy surfaces: Symmetric dissociation of water, N 2 , C 2 , and Be 2 journal, September 2015

iCI: Iterative CI toward full CI journal, January 2016

Fixed-node diffusion Monte Carlo potential energy curve of the fluorine molecule F 2 using selected configuration interaction trial wavefunctions journal, January 2015

Correlation energy extrapolation by intrinsic scaling. I. Method and application to the neon atom journal, January 2004

Correlation energy extrapolation by intrinsic scaling. II. The water and the nitrogen molecule journal, January 2004

Correlation energy extrapolation by intrinsic scaling. IV. Accurate binding energies of the homonuclear diatomic molecules carbon, nitrogen, oxygen, and fluorine journal, April 2005

Fragmentation Methods: A Route to Accurate Calculations on Large Systems journal, August 2011

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Energy-Based Molecular Fragmentation Methods journal, April 2015

The method of increments—a wavefunction-based ab initio correlation method for solids journal, May 2006

Accurate ab initio potential energy curve of F2. I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method journal, October 2007

Accurate ab initio potential energy curve of O2. I. Nonrelativistic full configuration interaction valence correlation by the correlation energy extrapolation by intrinsic scaling method journal, February 2010

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Accurate ab initio potential energy curves and spectroscopic properties of the four lowest singlet states of C2 journal, December 2013

Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen journal, January 1989

Direct configuration interaction and multiconfigurational self-consistent-field method for multiple active spaces with variable occupations. I. Method journal, November 2003

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An intersection seam between the ground state of ozone and an excited state of like symmetry a) journal, November 1990

Potential energy surfaces of ozone. I journal, June 1991

Strong shifts in diabatic nondynamic electron correlations cause conical intersection between low‐lying closed‐shell adiabatic singlets of like symmetry in ozone journal, September 1993

Global potential energy surfaces for the lowest two 1 A ′ states of ozone journal, August 1997

The intersection seam between the 1 1 A ′ and 2 1 A ′ states of ozone journal, August 1997

Theoretical results for the excited states of ozone journal, May 1972

Theoretical evidence for bound electronic excited states of ozone journal, December 1973

Theoretical Evidence for a Stable form of Cyclic Ozone, and its Chemical Consequences journal, January 1973

Theoretical investigation of the cyclic conformer of ozone journal, October 1974

The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study journal, March 2016

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A review on non‐relativistic, fully numerical electronic structure calculations on atoms and diatomic molecules journal, May 2019

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A priori identification of configurational deadwood
journal, February 2009

Fermion Monte Carlo without fixed nodes: A game of life, death, and annihilation in Slater determinant space
journal, January 2009

A deterministic alternative to the full configuration interaction quantum Monte Carlo method
journal, July 2016

Communication: An adaptive configuration interaction approach for strongly correlated electrons with tunable accuracy
journal, April 2016

Compressive sampling in configuration interaction wavefunctions
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Seniority number description of potential energy surfaces: Symmetric dissociation of water, N ₂ , C ₂ , and Be ₂
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iCI: Iterative CI toward full CI
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Fixed-node diffusion Monte Carlo potential energy curve of the fluorine molecule F ₂ using selected configuration interaction trial wavefunctions
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Correlation energy extrapolation by intrinsic scaling. I. Method and application to the neon atom
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Correlation energy extrapolation by intrinsic scaling. IV. Accurate binding energies of the homonuclear diatomic molecules carbon, nitrogen, oxygen, and fluorine
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Fragmentation Methods: A Route to Accurate Calculations on Large Systems
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Accurate ab initio potential energy curve of O2. I. Nonrelativistic full configuration interaction valence correlation by the correlation energy extrapolation by intrinsic scaling method
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Accurate ab initio potential energy curves and spectroscopic properties of the four lowest singlet states of C2
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Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen
journal, January 1989

Direct configuration interaction and multiconfigurational self-consistent-field method for multiple active spaces with variable occupations. I. Method
journal, November 2003

General atomic and molecular electronic structure system
journal, November 1993

An intersection seam between the ground state of ozone and an excited state of like symmetry ^a)
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Potential energy surfaces of ozone. I
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Strong shifts in diabatic nondynamic electron correlations cause conical intersection between low‐lying closed‐shell adiabatic singlets of like symmetry in ozone
journal, September 1993

Global potential energy surfaces for the lowest two 1 A ′ states of ozone
journal, August 1997

The intersection seam between the 1 1 A ′ and 2 1 A ′ states of ozone
journal, August 1997

Theoretical results for the excited states of ozone
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Theoretical evidence for bound electronic excited states of ozone
journal, December 1973

Theoretical Evidence for a Stable form of Cyclic Ozone, and its Chemical Consequences
journal, January 1973

Theoretical investigation of the cyclic conformer of ozone
journal, October 1974

The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study
journal, March 2016

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