Variational approach to charge transfer reactions in bridged triarylamine cations

In this work, we apply a recently proposed nonperturbative approach to the energetics of charge localization and charge transfer within molecules. The electronic structure of bridged organic donor–acceptor systems is described by a tight-binding Hamiltonian, which is extended by a nonretarded reaction field to account for the dielectric polarizability of the environment. The resulting Hamiltonian is solved self-consistently, and approximations to the potential energy curves for adiabatic self-exchange in the electronic ground state are obtained. The crossover from the localized (Day–Robin class I and II) to the delocalized (Day–Robin class IIIa) regime with decreasing bridge length is described. Kinetic parameters are computed by analyzing the potential energy curve of the charge transfer reaction. The limitations of the concept are discussed, and we give an outlook to its implementation for more elaborate electronic structure computations and advanced reaction fields.