A molecularly based theory for electron transfer reorganization energy

Journal Article · Mon Dec 14 00:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4936586· OSTI ID:22493323

Zhuang, Bilin; Wang, Zhen-Gang ^[1]

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1. Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States)

Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule’s permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory.

• OSTI ID: 22493323
• Journal Information: Journal of Chemical Physics, Vol. 143, Issue 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACTIVATION ENERGY
APPROXIMATIONS
DIELECTRIC MATERIALS
DIPOLE MOMENTS
ELECTRON TRANSFER
EQUILIBRIUM
FREE ENERGY
MOLECULES
POLARIZABILITY
POTENTIALS
SELF-CONSISTENT FIELD
SOLVATION
SOLVENTS
SPHERES
SURFACES