Errors are correlated against Γ CMO and Γ Boys in Fig. , using the same data set. As with Λ CMO , the metric Γ CMO does a reasonably good job of separating the localized excitations from the CT and Rydberg transitions, with errors in the CT transitions that increase in rough proportion to the value of Γ CMO . Here, the Boys-localized basis does not compress the data in the same way that it does with Λ. Part of this difference may stem from the fact that unlike Λ, which is bounded, Γ is not bounded except by the basis-set size. In addition, Boys-localized MOs need not (and typically do not) transform as irreducible representations of the molecular point group, which means that (∆r) Boys need not (and typically does not) vanish in the presence of inversion symmetry. This increases the value of Γ Boys relative to Γ CMO since (∆r) CMO = 0 in centrosymmetric molecules.