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.affiliation: Chemistry and Chemical Biology, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California 95343, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Dale
authors.affiliation: Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Erin R
authors.initials: ER
authors.lastname: Johnson
mesh_terms: D004247:DNA / Q000737:chemistry*; D004583:Electrons; D008956:Models, Chemical; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry
chemical_list: D012997:Solvents; D004247:DNA