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Title: Counterintuitive electron localisation from density-functional theory with polarisable solvent models

Abstract

Exploration of the solvated electron phenomena using density-functional theory (DFT) generally results in prediction of a localised electron within an induced solvent cavity. However, it is well known that DFT favours highly delocalised charges, rendering the localisation of a solvated electron unexpected. We explore the origins of this counterintuitive behaviour using a model Kevan-structure system. When a polarisable-continuum solvent model is included, it forces electron localisation by introducing a strong energetic bias that favours integer charges. This results in the formation of a large energetic barrier for charge-hopping and can cause the self-consistent field to become trapped in local minima thus converging to stable solutions that are higher in energy than the ground electronic state. Finally, since the bias towards integer charges is caused by the polarisable continuum, these findings will also apply to other classical polarisation corrections, as in combined quantum mechanics and molecular mechanics (QM/MM) methods. The implications for systems beyond the solvated electron, including cationic DNA bases, are discussed.

Authors:
 [1];  [2]
  1. Chemistry and Chemical Biology, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California 95343 (United States)
  2. Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2 (Canada)
Publication Date:
OSTI Identifier:
22493215
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 143; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CORRECTIONS; DENSITY FUNCTIONAL METHOD; DNA; POLARIZATION; QUANTUM MECHANICS; SELF-CONSISTENT FIELD; SOLUTIONS; SOLVATED ELECTRONS; SOLVENTS; TRAPPING

Citation Formats

Dale, Stephen G., E-mail: sdale@ucmerced.edu, and Johnson, Erin R., E-mail: erin.johnson@dal.ca. Counterintuitive electron localisation from density-functional theory with polarisable solvent models. United States: N. p., 2015. Web. doi:10.1063/1.4935177.
Dale, Stephen G., E-mail: sdale@ucmerced.edu, & Johnson, Erin R., E-mail: erin.johnson@dal.ca. Counterintuitive electron localisation from density-functional theory with polarisable solvent models. United States. doi:10.1063/1.4935177.
Dale, Stephen G., E-mail: sdale@ucmerced.edu, and Johnson, Erin R., E-mail: erin.johnson@dal.ca. Sat . "Counterintuitive electron localisation from density-functional theory with polarisable solvent models". United States. doi:10.1063/1.4935177.
@article{osti_22493215,
title = {Counterintuitive electron localisation from density-functional theory with polarisable solvent models},
author = {Dale, Stephen G., E-mail: sdale@ucmerced.edu and Johnson, Erin R., E-mail: erin.johnson@dal.ca},
abstractNote = {Exploration of the solvated electron phenomena using density-functional theory (DFT) generally results in prediction of a localised electron within an induced solvent cavity. However, it is well known that DFT favours highly delocalised charges, rendering the localisation of a solvated electron unexpected. We explore the origins of this counterintuitive behaviour using a model Kevan-structure system. When a polarisable-continuum solvent model is included, it forces electron localisation by introducing a strong energetic bias that favours integer charges. This results in the formation of a large energetic barrier for charge-hopping and can cause the self-consistent field to become trapped in local minima thus converging to stable solutions that are higher in energy than the ground electronic state. Finally, since the bias towards integer charges is caused by the polarisable continuum, these findings will also apply to other classical polarisation corrections, as in combined quantum mechanics and molecular mechanics (QM/MM) methods. The implications for systems beyond the solvated electron, including cationic DNA bases, are discussed.},
doi = {10.1063/1.4935177},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 18,
volume = 143,
place = {United States},
year = {2015},
month = {11}
}