Gian Luigi Bendazzoli, Muammar El Khatib, Stefano Evangelisti and Thierry Leininger
The total position spread tensor, Λ, is applied to a mixed-valence model system. This tensor is a measure of the electron delocalization, and it is very sensitive to the change of the nature of the wavefunction, in particular if associated to a charge transfer. For class II systems, there are geometrical configurations where low-lying electronic states present avoided-crossing. At that moment, the Λ shows a marked peak, indicating that there is a strong delocalization of the wavefunction.