A model for the prediction of electron-transfer rates in the highly exergonic region, applied to the reaction between solvated electrons and arenes in tetrahydrofuran

Abstract

Anharmonic oscillator perturbations to the classical model of outer-sphere electron-transfer reactions are examined and used to fit rate constant data in the exergonic Marcus-invented region. Oscillator energy functions of the type G(x)=ax²(1 +bx²) and G(x)=ax²(1 +bx²+cx⁴) are used. Here x is the reaction co-ordinate for electron transfer which has the value zero at the origin of the donor and unity at the origin of the acceptor. The function G(x)=ax²[1 +bx²/[graphic ommitted])], where a, b, and c are constants, an oscillator with variable anharmonicity term, very successfully reproduces the data for reaction between solvated electrons and arenes in tetrahydrofuran. Such a model will be useful in constructing the energy surface for single-electron-transfer reactions.