High nuclearity mixed-valence magnetic clusters: theoretical study of the spin coupling in the C602− fulleride ion

The problem of delocalization of a pair of electrons over the fullerene C60 is considered, with the aim of elucidating the nature of the ground spin state, as well as the structure of the low-lying energy levels in this mixed-valence molecule C602−. A model that considers the Coulomb interactions between the two extra electrons, as well as the two single-electron transfer processes involved in the electron delocalization, is developed. The influence of these electronic parameters on the spectrum of the low-lying energy levels is discussed. We find that the ground state is always a spin singlet, whatever the relative values of these parameters are.