Next, we consider the performance of both tuning schemes for a benchmark set of small open-shell and "exotic" molecules. Tuned TD-LRC-ωPBE results are listed in Table and we observe large differences between ω IE and ω GDD in some cases, yet excitation energies are often quite similar. For example, in NH 2 the excitation energies differ by less than 0.1 eV even though the tuned ω values differ by 0.13 bohr -1 . For the NCO and OH radicals, however, TD-LRC-ω IE PBE and TD-LRC-ω GDD PBE excitation energies differ by 0.6 eV and 0.9 eV, respectively, and the ω IE values are unusually large. Even more striking is the failure to determine ω IE for the CN radical, for which IE tuning sends ω → ∞.