Despite a clear success of the FDE-diab approach in predicting qualitatively correct spindensity distributions, this methodology as well as the computational protocol used in this work still leave room for improvements. Unambiguous predictions of spin-density delocalizations over multiple subsystems are not possible within the described above twostate model. These calculations would require a generalization of the FDE-diab towards multiple quasi-diabatic states. Another aspect to be mentioned is the use of rigid molecular structures, which does not account for dynamical effects such as thermal molecular motion. These effects are known to have a large influence on MO energies .