"Experiments and Simulations of Bimolecular Electron Transfer and Solvent Dynamics"
The description of electron transfer (ET) processes has been greatly aided by Marcus theory, a linear-response theory based on a model of spherical reactants immersed in a continuum solvent. While this model has found considerable practical success, most analyses of ET reactions disregard the molecular nature of the system. In addition to equilibrium energetic properties, the rates many ET reactions are also governed by local solvent motions. Because many of the parameters underlying Marcus theory are not directly accessible by experiment, we must use detailed computer simulations to probe how the molecular nature of the solute and solvent manifests in the dynamics of electron transfer reactions. We will present the results of NMR experiments and MD simulations which explore bimolecular electron donor/acceptor systems and local solvent dynamics at a molecular level. We are able to show that the spherical solute/continuum solvent model can be a poor description of real ET systems and how they could lead to misinterpretations of experimental data. We will also discuss how NMR T 1 relaxation measurements in conjunction with detailed simulations can be a powerful tool for studying local solvent dynamics around a diverse set of monatomic ion solutes. These experiments and simulations will help us shed light on the molecular details of ET reactions that neither method could provide in isolation.