A THEORY OF ADIABATIC BOND BREAKING ELECTRON-TRANSFER REACTIONS AT METAL-ELECTRODES

A theory is formulated for bond breaking and electron transfer at meta l electrodes, based on an adaptation of the Anderson-Newns Hamiltonian . The model provides an extension of Saveant's model for concerted bon d breaking and electron transfer and yields Saveant's predictions in t he limit of vanishing electronic coupling. Solvent dynamical effects a re investigated by assuming an overdamped solvent motion and a ballist ic bond breaking motion. It is found that in a sufficiently slow solve nt the transfer coefficient and the activation enthalpy may become tem perature dependent, although the effect is probably small for most com binations of redox couples and solvents nr room temperature. (C) 1998 Elsevier Science B.V.