states of linear acene molecules 116 have attracted considerable interest because 1 L b is accurately described by global hybrid functionals such as B3LYP but 1 L a is not. The latter exhibits ionic character that is not detected by standard metrics such as Λ CMO . For each of the acenes in Tozer's data set (naphthalene through hexacene), we find that 1 L a is well described by one principal NTO pair but 1 L b requires two pairs. Representative results for hexacene are shown in Fig. , in- cluding principal NTOs and the metrics Γ NTO and d CD1 .