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Rehm–Weller equation

Empirical correlation found between the observed second-order rate constant, k q, for an intermolecular electron-transfer reaction and the Gibbs energy of the photoinduced electron transfer process within the encounter complex (Δ ET G o):
k q = k d 1 + k d K d Z exp ( Δ G ‡ R T ) + exp ( Δ ET G o R T )
with k d and k −d the rate constant for the formation and separation, respectively, of the encounter (precursor) complex, K d = k d k −d, Z the universal collision frequency factor, R the gas constant, T the absolute temperature and Δ G ‡ the activation Gibbs energy of the forward electron transfer reaction.
In the original formulation of this equation the value k d K d Z = 0.25 in acetonitrile was used.
PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 413
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IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.RT07472.
Original PDF version: http://www.iupac.org/goldbook/RT07472.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
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