Resolving the Marcus-Rehm-Weller Paradox in Electron Transfer
The paper resolves a paradox between Marcus theory (predicting rate decrease with increasing driving force) and Rehm-Weller kinetics (predicting rate saturation). It uses a single two-state quantum Hamiltonian to show that Marcus kinetics occur in the nonadiabatic limit, while Rehm-Weller behavior emerges in the adiabatic limit. This is explained by introducing an 'effective reorganization energy' that interpolates between the two kinetic regimes.