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DOI: 10.1039/A707592H (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1998, 603-606

Determination of unimolecular rate data from reaction mid-point temperatures derived from EPR spectra

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John C. Walton

Abstract

The activation energies of unimolecular homolytic reactions (Er) are predicted to correlate linearly with the mid-point temperatures (Tmid) defined as the temperature at which the rearranged and unrearranged species are of equal concentration, for photochemically initiated processes under EPR conditions. A linear relationship (Er/kcal mol–1 = 0.044Tmid + 0.22) has been demonstrated from experimental data and shown to hold for a range of solvents and instrumental configurations. The relationship will facilitate the determination of kinetic parameters, particularly for processes where the spectra of the intermediates are of low intensity.

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