Group theoretical classification of electronic states in mixed-valence complexes

A group theoretical method is developed to treat the ground and excited electronic states of multielectronic polynuclear mixed-valence systems of the general form dn–…–dn–dn+1–…–dn+1 and fn–…–fn–fn+1–…–fn+1. Effects arising from electronic degeneracy, spin–orbit interactions and reduced site symmetry are explicitly taken into account. The versatility of the technique is demonstrated by applying it to a series of trimeric mixed-valence clusters.