Electron transfer between magnetic ions in mixed valence binuclear systems

Abstract

This paper describes how the Hubbard model in the atomic limit implemented by taking into account molecular vibrations can give a description of mixed valence binuclear systems with both metallic ions simultaneously magnetic. A FeIII (high spin) FeII (high spin) binuclear complex would constitute an example. In such systems electron transfer and electron exchange are expected. If the compound belongs to class II (Robin and Day classification) we find that the activation energy of the thermal electron transfer and the intensity of the intervalence band are spin dependent but that the energies of spin states are given by the Heisenberg Hamiltonian with a new expression for the exchange parameter. For class III binuclear complexes a quite different behavior is found. The energy of the intervalence band is spin dependent but energies of spin states are no longer given by the Heisenberg Hamiltonian.