where τ d represents the initial delay time for the system remaining in the S 1 state and τ e is the time constant for the exponential decay. The overall lifetime is τ d + τ e , which is technically the time required for the S 1 population to drop to 1/e of its initial value p(0) = 1. We fit the data in Fig. (a) to this functional form, and the time constants thus obtained (for each level of theory) are listed in Table . Uncertainties listed in the table were obtained using the bootstrap method. The two LR-TDDFT methods predict much longer lifetimes for the S 1 state as compared to SF-BH&HLYP and CASSCF. In the latter two methods, most of the trajectories are trapped at the local minimum S 1min (C 1 C 2 ), where the molecules have to overcome a large barrier before the conical seam at MECP(C 2 C 3 ) can be reached; see Fig. . That LR-ωB97X/TDA predicts a longer lifetime for the S 1 state as compared to LR-ωB97X is also consistent with the larger barrier predicted by the former as compared to the latter. In Figure , we plot the averaged BLA coordinate values during the simulations. For LR-ωB97X, either with and without the TDA, the BLA does not decrease to an extent such that the reaction coordinate (corresponding to C 2 =C 3 torsion) can be activated, therefore only a few of the trajectories manage to return to the S 0 state via nonadiabatic transitions at MECP(C 2 C 3 ). This is more clear in Fig. , where the distribution of the torsion angle around C 2 =C 3 is plotted for each of the three DFT methods. In the case of SF-BH&HLYP, about 90% of the trajectories returned to the S 0 state on the timescale of the simulation, with 56% of them forming the cis pho- toproduct. For LR-ωB97X, however, only 40% of the trajectories underwent S 1 → S 0 deactivation within the 218 fs timescale that we simulate, and amongst those that do return to the ground state, 43% relaxed to the cis isomer. Even fewer transitions were observed at the LR-ωB97X/TDA level, which amounts to 14% of the total number of trajectories, and 25% of the nonadiabatic transitions lead to the cis isomer. If we further plot the distribution of the torsion angle for the C 1 -C 2 single bond [Fig. (b)], we find that most of the trajectories computed by the two LR-TDDFT methods follow the reaction pathways of C 1 -C 2 twisting, especially at the LR-ωB97X/TDA level. This corresponds either to trapping at S 1min (C 1 C 2 ) or hopping at MECP(NC 1 ). The latter explains the observation of fewer cis photoproducts in the LR-TDDFT trajectories as well as the smaller delay time τ d , as compared to SF-BH&HLYP simulations.