The solvent contribution lambda(s) to the reorganization energy of electron transfer can be estimated from averages of the potential energy gaps between neutral-pair and ion-pair states over an ensemble of structures generated from molecular dynamics simulations. Invoking a Marcus-type two-sphere model for charge separation and recombination in an aqueous environment, we explored the effect of a polarizable force field and noted a strong reduction of lambda(s) (by approximately 45%) compared to the corresponding value obtained with a standard nonpolarizable force field. Both types of force fields yield lambda(s) values that in agreement with the Marcus theory, vary strictly linearly with the inverse of the donor-acceptor distance; the corresponding slopes translate into appropriate effective optical dielectric constants, epsilon(infinity) approximately 1.0+/-0.2 for a nonpolarizable and epsilon(infinity) approximately 1.7+/-0.4 for a polarizable force field. The reduction in the solvent reorganization energy due to a polarizable force field translates into a scaling factor that is essentially independent of the donor-acceptor distance. The corresponding effective optical dielectric constant, epsilon(infinity) approximately 1.80, is in excellent agreement with experiment for water.
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J Mol Model
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Shanxi Jiangyang Chemical Limited Company, Taiyuan, 030041, Shanxi, China.
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Central European Institute of Technology, Masaryk University, Brno60200, Czech Republic.
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View Article and Find Full Text PDFACS Appl Mater Interfaces
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View Article and Find Full Text PDFJ Chem Theory Comput
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Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
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