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Does the DFT Self-Interaction Error Affect Energies Calculated in Proteins with Large QM Systems?

Fouda, Adam and Ryde, Ulf LU (2016) In Journal of Chemical Theory and Computation 12(11). p.5667-5679
Abstract

We have examined how the self-interaction error in density-functional theory (DFT) calculations affects energies calculated on large systems (600-1000 atoms) involving several charged groups. We employ 18 different quantum mechanical (QM) methods, including Hartree-Fock, as well as pure, hybrid, and range-separated DFT methods. They are used to calculate reaction and activation energies for three different protein models in vacuum, in a point-charge surrounding, or with a continuum-solvent model. We show that pure DFT functionals give rise to a significant delocalization of the charges in charged groups in the protein, typically by 0.1 e, as evidenced from the Mulliken charges. This has a clear effect on how the surroundings affect... (More)

We have examined how the self-interaction error in density-functional theory (DFT) calculations affects energies calculated on large systems (600-1000 atoms) involving several charged groups. We employ 18 different quantum mechanical (QM) methods, including Hartree-Fock, as well as pure, hybrid, and range-separated DFT methods. They are used to calculate reaction and activation energies for three different protein models in vacuum, in a point-charge surrounding, or with a continuum-solvent model. We show that pure DFT functionals give rise to a significant delocalization of the charges in charged groups in the protein, typically by 0.1 e, as evidenced from the Mulliken charges. This has a clear effect on how the surroundings affect calculated reaction and activation energies, indicating that these methods should be avoided for DFT calculations on large systems. Fortunately, methods such as CAM-B3LYP, BHLYP, and M06-2X give results that agree within a few kilojoules per mole, especially when the calculations are performed in a point-charge surrounding. Therefore, we recommend these methods to estimate the effect of the surroundings with large QM systems (but other QM methods may be used to study the intrinsic reaction and activation energies).

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Theory and Computation
volume
12
issue
11
pages
13 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84996938073
  • wos:000387519400040
ISSN
1549-9618
DOI
10.1021/acs.jctc.6b00903
language
English
LU publication?
yes
id
6a4a4694-ccd2-4a21-9a60-0f5c4393630c
date added to LUP
2016-12-12 10:17:09
date last changed
2017-11-19 04:35:51
@article{6a4a4694-ccd2-4a21-9a60-0f5c4393630c,
  abstract     = {<p>We have examined how the self-interaction error in density-functional theory (DFT) calculations affects energies calculated on large systems (600-1000 atoms) involving several charged groups. We employ 18 different quantum mechanical (QM) methods, including Hartree-Fock, as well as pure, hybrid, and range-separated DFT methods. They are used to calculate reaction and activation energies for three different protein models in vacuum, in a point-charge surrounding, or with a continuum-solvent model. We show that pure DFT functionals give rise to a significant delocalization of the charges in charged groups in the protein, typically by 0.1 e, as evidenced from the Mulliken charges. This has a clear effect on how the surroundings affect calculated reaction and activation energies, indicating that these methods should be avoided for DFT calculations on large systems. Fortunately, methods such as CAM-B3LYP, BHLYP, and M06-2X give results that agree within a few kilojoules per mole, especially when the calculations are performed in a point-charge surrounding. Therefore, we recommend these methods to estimate the effect of the surroundings with large QM systems (but other QM methods may be used to study the intrinsic reaction and activation energies).</p>},
  author       = {Fouda, Adam and Ryde, Ulf},
  issn         = {1549-9618},
  language     = {eng},
  month        = {11},
  number       = {11},
  pages        = {5667--5679},
  publisher    = {The American Chemical Society},
  series       = {Journal of Chemical Theory and Computation},
  title        = {Does the DFT Self-Interaction Error Affect Energies Calculated in Proteins with Large QM Systems?},
  url          = {http://dx.doi.org/10.1021/acs.jctc.6b00903},
  volume       = {12},
  year         = {2016},
}