Although these two tuned LRC functionals perform equally well for acene excitation energies, they yield different results for other acene properties. HOMO/LUMO gaps for the acene sequence are known to decrease much faster than the corresponding gaps for the cyclohexanebased perhydroacenes, and application of IE tuning to the linear acenes suggests that ω IE → 0 as the number of rings increases. In fact, the decay rate of ω IE is much faster than that of ω GDD , as shown in Fig. . The GDD-tuned value appears to be approaching a characteristic length scale 1/ω GDD ≈ 4 bohr that is comparable to the size of one benzene ring (4.645 bohr), whereas 1/ω IE > 4 bohr except in the case of naphthalene.