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Density-Functional Errors in Alkanes: A Real-Space Perspective.

Publication ,  Journal Article
Johnson, ER; Contreras-García, J; Yang, W
Published in: Journal of chemical theory and computation
August 2012

Density-functional theory (DFT) approximations are known to give systematic errors for isodesmic reaction energies of n-alkanes to form ethane. Several explanations have been proposed, involving both the exchange or correlation nature of the problem and its distance range (i.e., medium-range or long-range interactions). In this work, a new isodesmic reaction is defined to demonstrate that the reaction energy differences originate from localized interactions between contiguous CH2 units in the n-alkane, i.e., from 1,3 interactions. Furthermore, we introduce a real-space interpretation of the error based on changes in electron density, described by our recently developed Non-Covalent Interactions (NCI) method. The reduced density gradient has smaller values for noncovalent 1,3 interactions in n-alkane reactants compared to ethane products. The gradient contribution to the exchange energy is consequently reduced, giving a constant energy bias against each propane unit in an n-alkane. Differences in exchange energy for grid points within the NCI regions are shown to be responsible for the reaction-energy errors. This is also demonstrated to be the source of error in Diels-Alder addition barrier heights obtained with GGA-based hybrid functionals.

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Published In

Journal of chemical theory and computation

DOI

EISSN

1549-9626

ISSN

1549-9618

Publication Date

August 2012

Volume

8

Issue

8

Start / End Page

2676 / 2681

Related Subject Headings

  • Chemical Physics
  • 3407 Theoretical and computational chemistry
  • 3406 Physical chemistry
  • 0803 Computer Software
  • 0601 Biochemistry and Cell Biology
  • 0307 Theoretical and Computational Chemistry
 

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Johnson, E. R., Contreras-García, J., & Yang, W. (2012). Density-Functional Errors in Alkanes: A Real-Space Perspective. Journal of Chemical Theory and Computation, 8(8), 2676–2681. https://doi.org/10.1021/ct300412g
Johnson, Erin R., Julia Contreras-García, and Weitao Yang. “Density-Functional Errors in Alkanes: A Real-Space Perspective.Journal of Chemical Theory and Computation 8, no. 8 (August 2012): 2676–81. https://doi.org/10.1021/ct300412g.
Johnson ER, Contreras-García J, Yang W. Density-Functional Errors in Alkanes: A Real-Space Perspective. Journal of chemical theory and computation. 2012 Aug;8(8):2676–81.
Johnson, Erin R., et al. “Density-Functional Errors in Alkanes: A Real-Space Perspective.Journal of Chemical Theory and Computation, vol. 8, no. 8, Aug. 2012, pp. 2676–81. Epmc, doi:10.1021/ct300412g.
Johnson ER, Contreras-García J, Yang W. Density-Functional Errors in Alkanes: A Real-Space Perspective. Journal of chemical theory and computation. 2012 Aug;8(8):2676–2681.
Journal cover image

Published In

Journal of chemical theory and computation

DOI

EISSN

1549-9626

ISSN

1549-9618

Publication Date

August 2012

Volume

8

Issue

8

Start / End Page

2676 / 2681

Related Subject Headings

  • Chemical Physics
  • 3407 Theoretical and computational chemistry
  • 3406 Physical chemistry
  • 0803 Computer Software
  • 0601 Biochemistry and Cell Biology
  • 0307 Theoretical and Computational Chemistry