The excitation energies and oscillator strengths for the models described above were computed using linear response time-dependent (TD) methods (Hartree-Fock, DFT, and semiempirical) and the configuration interaction singles (CIS) scheme. We used two global hybrid functionals, B3LYP (20 % of exact exchange) and BHandHLYP (50 % of exact exchange; as implemented in the Gaussian package, for "half-and-half" theory see Ref. 54), and five range-separated hybrid functionals, CAM-B3LYP 55 , M11 56 , ωB97 57 , ωB97X 57 , and ωB97X-D . We also used TD-HF, ab initio CIS, as well as TD and CIS methods in combination with AM1 59 and PM7 60 semiempirical methods. In addition, the long-range corrected density functional tight binding method (TD-lc-DFTB) was tested. For calculations with non-semiempirical methods the def2-SV(P) basis set was used. Absorption spectra were calculated using excitation energies and oscillator strengths as: