A theory of adiabatic bond breaking electron transfer reactions at metal electrodes

A theory is formulated for bond breaking and electron transfer at metal electrodes, based on an adaptation of the Anderson-Newns Hamiltonian. The model provides an extension of Saveant's model for concerted bond breaking and electron transfer and yields Saveant's predictions in the limit of vanishing electronic coupling. Solvent dynamical effects are investigated by assuming an overdamped solvent motion and a ballistic bond breaking motion. It is found that in a sufficiently slow solvent the transfer coefficient and the activation enthalpy may become temperature dependent, although the effect is probably small for most combinations of redox couples and solvents nr room temperature. (C) 1998 Elsevier Science B.V.