A molecularly based theory for electron transfer reorganization energy

Abstract

Articles you may be interested inUsing 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. C 2015 AIP Publishing LLC. [http://dx

Comparative Analysis of Type IV Pilin in Desulfuromonadales

“…Moreover, the reorganization energy that contributed to the electron transfer activation energy of tyrosine was reported to be stronger than it was for phenylalanine (Yan et al, 2015). When pi-pi interactions are forming, the more electron transfer activation energy there is, the better the conductive effect the aromatic amino acids may have (Zhuang and Wang, 2015). Feliciano et al (2015) reported that two mutations (Y32A (alanine), and Y57A) in the pilin amino acid sequence severely affected the function of pili as an electronic conduit in vivo .…”

Solvation Energy of Ions in Polymers: Effects of Chain Length and Connectivity on Saturated Dipoles near Ions

“…Indeed, we found that the discrepancy between the coarse-grained mean-field theory and the simulation arises from the chain-like association of the dipoles due to the strong dipole–dipole interaction (Figure ). Thus, we suggest the further development of coarse-grained mean-field theories for ion solvation in polymers, along the same lines as the recent theoretical trends such as the use of a hybrid of self-consistent field theory and integral-equation theory, , modified Poisson–Boltzmann equation, − and dipolar self-consistent field theory . In the context of the ion-containing polymers, further analysis of the nonmonotonic variation in the dipolar orientation under the external electrostatic field or the stress field would also provide valuable insight into the birefringence of dielectrics in electro-optics.…”

Molecular-Based Theory for Electron-Transfer Reorganization Energy in Solvent Mixtures

“…Using statistical-field techniques, we decouple the quadratic interactions between the charge density with a series of identity transformations. The procedure for the transformations is similar to that presented in our earlier work in ref , and it leads to the following exact field-theoretic partition function with the effective field Hamiltonian H given by where ρ­( r ) = ρ̂ c ( r ) + ρ or ( r ) + ρ el ( r ), and Q S is the single-particle partition function in the fields w S ( r ), w or ( r ), and w el ( r )­ Here, Γ­( r ) serves to limit the integration to space outside the solute cavity, with Γ­( r ) = 0 if and 1 otherwise. The transformation to the field-theoretic partition function has introduced the coarse-grained charge density fields ρ or and ρ el for the solvent permanent and induced dipoles, respectively; w or and w el are the scaled orientational and electronic electric potentials that are the conjugate fluctuating fields to ρ or and ρ el , respectively.…”

“…In computing the reorganization energy, the integral only needs to be evaluated for the region outside the cavity by referencing the free energy to a vacuum state with the same charge distribution. Details for the procedure are given in Appendix B of ref .…”

“…Recently, we developed a molecular-based dipolar self-consistent-field theory (DSCFT) for calculating reorganization energies in pure liquids using statistical-field techniques . The theory models the polarizable solvent molecules using a few readily available molecular parameters, including the permanent dipole moment, the polarizability, and the molecular volume.…”