Vol. 7 No. 1 (2023)
Research Articles

The Rate Constant - Reaction Free Energy Dependence for the Electron Transfer Reactions in Solutions. The Way to Interpret the Experimental Data Correctly

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  • Lev I. Krishtalik
Lev I. Krishtalik
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow
Image of Lev Krishtalik
DOI: https://doi.org/10.36253/Substantia-1872

Published 2023-02-08

Keywords

  • Reorganization energy,
  • Medium reorganization,
  • Intra-molecular reorganization,
  • Rate maximum

How to Cite

Krishtalik, L. I. (2023). The Rate Constant - Reaction Free Energy Dependence for the Electron Transfer Reactions in Solutions. The Way to Interpret the Experimental Data Correctly. Substantia, 7(1), 15–22. https://doi.org/10.36253/Substantia-1872

Copyright (c) 2023 Lev I. Krishtalik

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This work is licensed under a Creative Commons Attribution 4.0 International License.

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Abstract

The relative influences of the reorganization energies of the classical and quantum modes on the maximum position of the rate constant – reaction free energy curve have been studied. In the framework of the continuum electrostatics, the electron transfer reorganization energies in methyltetrahydrofurane solutions for the system biphenylyl – spacer – acceptor were calculated. For different acceptors the solvent reorganization energy varies from 1.0 to 1.1 eV. When added with the rather small reorganization energies for classical intra-molecular modes we obtain 1.13 - 1.34 eV. With account of possible errors this coincides practically with the experimental estimate of the energy at the maximum of the rate–free energy curve DGmax ? -1.2 eV. Hence, we can conclude that the reorganization of quantum modes does not influence substantially the position of this maximum. To the contrary, in a non-polar solvent isooctane were the solvent reorganization does not play any role the reorganization of the quantum intra-reactants modes becomes determinant. These conclusions agree fully with the results of the general theoretical analysis and should be accounted for in the experimental data interpretation.

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