which indicates what the procedure entails, namely, a sequence of LRC-DFT calculations for both the molecule and its cation, using different values of ω, in order to determine the optimal value ω IE that satisfies eq. 4. This is expensive for large molecules and tedious in any case, and there is no guarantee that such a value exists. In particular, IE-tuning can be fraught for small-gap systems, which drive the optimally tuned value of ω towards zero, corresponding to a functional that eliminates E LR x,HF . This small-gap behavior is noteworthy because semilocal GGA functionals tend toward vanishing gaps for large systems. Problems with IE tuning have been observed in large conjugated π systems, long-chain alkanes, 32 nanoscale materials, and large water cluster anions. For periodic systems, where introducing a net charge is problematic, IE tuning must be done carefully, based on localized orbitals. In the present work, we consider TD-DFT applications using LRC functionals with an alternative (and automatic) means to determine ω, in a system-specific way, based on a global density-dependent (GDD) tun- , including more than one transition for some of these molecules ing procedure. Here, the range-separation parameter is determined according to