There have so far been only a few TSH studies using SF-TDDFT. Yue et al. used this approach to make a first-principles investigation of the mechanism of firefly bioluminescence, specifically, the photoinitiated decomposition reaction to form the anionic emitter species, oxyluciferin. Nakai and co-workers recently implemented SF-TDDFT at the level of semi-empirical density-functional tight-binding ("DFTB"), and have used the method to perform TSH simulations of the archetypal azobenzene photoisomerization, in explicit solvent. Lastly, Minezawa and Nakajima have simulated S 1 lifetimes for several small molecules, demonstrating good agreement with previous TSH simulations employing multireference electronic structure methods. That study recognizes the fact because LR-TDDFT may skew the topology of CXs that involve the ground state, TSH simulations that employ LR-TDDFT ought to be terminated prior to the final internal conversion step that returns the molecule to its ground state. If this paradigm is followed then S 1 lifetimes are inaccessible to LR-TDDFT simulations, whereas SF-TDDFT suffers no such limitation.