This analysis has been idealized in the sense that it assumes orthonormal basis functions, and is intended to demonstrate simply that the aforementioned metrics are capable of distinguishing between delocalized states and thus providing information that ∆ρ elec and ∆ρ hole do not. As discussed also in Section 4.2, these metrics rely on our ability to assign amplitudes x µν to atoms and are susceptible to all of the usual problems with Mulliken and Löwdin charge analysis. That said, this type of analysis has been used in real calculations to classify the excited states of π-stacked dimers of naphthalene, 186 adenine, and pyridine, for example.