EFFECTIVE COUPLING IN BRIDGED ELECTRON-TRANSFER MOLECULES - COMPUTATIONAL FORMULATION AND EXAMPLES

The effective electronic donor/acceptor coupling (H(DA)) for a bridged electron transfer system is defined. An expression for H(DA) in terms of the bridge Green's function is developed for systems represented by a tight-binding Hamiltonian. H(DA) is computed exactly for two systems and the existence of a dimensionless parameter which determines whether the effective coupling oscillates or decays with increasing donor/acceptor distance is demonstrated. A numerical technique for computing H(DA) is developed and shown to be significantly more powerful than conventional techniques.