Contrarily to the prediction of the semi-classical Marcus theory, the rate constant of charge recombination (CR) of excited donor-acceptor complexes (DACs) does not exhibit a bell-shaped free energy dependence, but rather shows a linear relationship when plotted in a logarithmic scale . Moreover, this behavior continues down to very low driving forces, and the so-called normal region, i.e. the decrease of the rate constant with decreasing exergonicity, is not observed. There has been several hypothesis to account for this discrepancy, including variation of other parameters than free energy when going from one DAC to another and non-equilibrium dynamic effects , but there is still no conclusive explanation.
© 2002 Optical Society of AmericaPDF Article