Free energy, entropy and volume of activation for electron transfer reactions in a polar solvent
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
A continuum theory with account of cavity size fluctuations is employed to study free energy, volume and entropy of activation for nonadiabatic electron transfer (ET) reactions in polar solvents. By using a two-sphere cavity description, model calculations are performed for charge separation and recombination processes in acetonitrile under ambient conditions. It is found that the cavity size at the transition state varies with the free energy of reaction as well as with the thermodynamic conditions. In contrast to the Marcus theory predictions, the volume and entropy of activation show a monotonic behavior with the free energy of reaction and a strong correlation with each other. For example, for a given ET process, the volume and entropy of activation have the same sign. Their values for the charge separation and recombination processes are opposite in sign. These findings are in good qualitative agreement with measurements.
- OSTI ID:
- 20864264
- Journal Information:
- Journal of Chemical Physics, Vol. 125, Issue 1; Other Information: DOI: 10.1063/1.2217941; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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