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Title: The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent

Abstract

The intermolecular electron transfer in a solute pair consisting of pyrene and dimethylaniline is investigated in a nonpolar solvent, n-hexane. The earlier elaborated approach [M. Tachiya, J. Phys Chem. 97, 5911 (1993)] is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses for both nonpolarizable and polarizable molecular level simulations. The molecular-dynamics technique was implemented for obtaining the equilibrium ensemble of solvent configurations. The nonpolar solvent, n-hexane, was treated in terms of OPLS-AA parametrization. Solute Lennard-Jones parameters were taken from the same parametrization. Solute charge distributions of the initial and final states were determined using ab initio level [HF/6-31G(d,p)] quantum-chemical calculations. Configuration analysis was performed explicitly taking into account the anisotropic polarizability of n-hexane. It is shown that the Gaussian law well describes calculated distribution functions of the solvent coordinate, therefore, the rate constant of the ET reaction can be characterized by the reorganization energy. Evaluated values of the reorganization energies are in a range of 0.03-0.11 eV and significant contribution (more then 40% of magnitude) comes from anisotropic polarizability. Investigation of the reorganization energy {lambda} dependence on the solute pair separation distance d revealed unexpected behavior. The dependence has a very sharp peakmore » at the distance d=7 A where solvent molecules are able to penetrate into the intermediate space between the solute pair. The reason for such behavior is clarified. This new effect has a purely molecular origin and cannot be described within conventional continuum solvent models.« less

Authors:
;  [1]
  1. National Institute of Advanced Industrial Science and Technology, AIST Central 5, Tsukuba, Ibaraki 305-8565 (Japan)
Publication Date:
OSTI Identifier:
20723270
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 123; Journal Issue: 22; Other Information: DOI: 10.1063/1.2131054; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANISOTROPY; CHARGE DISTRIBUTION; CHARGE EXCHANGE; DISTRIBUTION FUNCTIONS; ELECTRON TRANSFER; HARTREE-FOCK METHOD; HEXANE; LENNARD-JONES POTENTIAL; MILLI EV RANGE; MOLECULAR DYNAMICS METHOD; POLARIZABILITY; PYRENE; REACTION KINETICS; SIMULATION; SOLUTES; SOLVENTS

Citation Formats

Leontyev, I.V., and Tachiya, M. The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent. United States: N. p., 2005. Web. doi:10.1063/1.2131054.
Leontyev, I.V., & Tachiya, M. The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent. United States. doi:10.1063/1.2131054.
Leontyev, I.V., and Tachiya, M. Thu . "The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent". United States. doi:10.1063/1.2131054.
@article{osti_20723270,
title = {The reorganization energy of electron transfer in nonpolar solvents: Molecular level treatment of the solvent},
author = {Leontyev, I.V. and Tachiya, M.},
abstractNote = {The intermolecular electron transfer in a solute pair consisting of pyrene and dimethylaniline is investigated in a nonpolar solvent, n-hexane. The earlier elaborated approach [M. Tachiya, J. Phys Chem. 97, 5911 (1993)] is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses for both nonpolarizable and polarizable molecular level simulations. The molecular-dynamics technique was implemented for obtaining the equilibrium ensemble of solvent configurations. The nonpolar solvent, n-hexane, was treated in terms of OPLS-AA parametrization. Solute Lennard-Jones parameters were taken from the same parametrization. Solute charge distributions of the initial and final states were determined using ab initio level [HF/6-31G(d,p)] quantum-chemical calculations. Configuration analysis was performed explicitly taking into account the anisotropic polarizability of n-hexane. It is shown that the Gaussian law well describes calculated distribution functions of the solvent coordinate, therefore, the rate constant of the ET reaction can be characterized by the reorganization energy. Evaluated values of the reorganization energies are in a range of 0.03-0.11 eV and significant contribution (more then 40% of magnitude) comes from anisotropic polarizability. Investigation of the reorganization energy {lambda} dependence on the solute pair separation distance d revealed unexpected behavior. The dependence has a very sharp peak at the distance d=7 A where solvent molecules are able to penetrate into the intermediate space between the solute pair. The reason for such behavior is clarified. This new effect has a purely molecular origin and cannot be described within conventional continuum solvent models.},
doi = {10.1063/1.2131054},
journal = {Journal of Chemical Physics},
number = 22,
volume = 123,
place = {United States},
year = {Thu Dec 08 00:00:00 EST 2005},
month = {Thu Dec 08 00:00:00 EST 2005}
}