For Ada-CN + , the brightest among low-lying states was found to be the D 2 state for B3LYP and CAM-B3LYP, while for the semiempirical CISD method, it is D 3 . The excitation energies (and oscillator strengths) for this bright transition are 1.25 eV (0.06), 1.25 eV (0.06), and 1.98 eV (0.12) at the B3LYP, CAM-B3LYP, and ROOM3/CISD(12 × 10) level, respectively. Note that for the semiempirical calculations, in the case of Ada-CN + , we changed the active space from 9 × 10 to 12 × 10. This choice was made by inspecting orbitals (in TD-DFT and semiempirical CISD calculations) involved in the higher energy bright transition corresponding to the second band in the experimental spectrum (D 11 in the study of Crandall et al. ). This higher energy bright transition is also listed in Tab. 1. It is located at 3.77 eV, 3.82 eV, and 4.14 eV according to B3LYP, CAM-B3LYP, and ROOM3/CISD, respectively. The corresponding bright state is D 11 at the TD-DFT levels (in agreement with the recent TD-DFT calculations of Crandall et al. ) and D 8 at the ROOM3/CISD(12 × 10) level (at the optimized UB3LYP/6-31G* geometry). Here, we note that ROOM3/CISD(12 × 10) calculations at the optimized ROOM3/CISD(12 × 10) geometry yield this bright state as D 11 (as in the TD-DFT case).