Then, "back" hops will be more frequent with smaller values of the Gaussian widths, ultimately extending the lifetimes. Notably, when only active atoms are considered in the calculation of the quantum momentum, the values of the widths are 3-4 times smaller than corresponding values when all coordinates are used, both in the frozen-Gaussian and in thawed-Gaussian options (see Fig. ). In particular, upon analysis of Fig. , it becomes evident that the CT-TSH-TGLA approach displays significantly more frequent fluctuations in the state probabilities compared to the other methodologies, which contributes to an increased occurrence of "back" hops, and, as a result, a longer lifetime of the S 2 state is observed. As shown in Fig. and 10, a significant number of trajectories became lonely when frozen Gaussians are used to compute the quantum momentum. In particular, when considering all atoms for the computation of the quantum momentum, approximately 77% and 78% of trajectories became lonely by the end of the dynamics when the trajectories start on the nπ * and ππ * states, respectively. However, when we limit the active atoms to the carbon and nitrogen atoms bridging the phenyl groups we observe a decrease of the fraction of lonely trajectories to 45% for the trajectories started in the nπ * state, and to 72% for the trajectories started in the ππ * state. This suggests that utilizing fewer coordinates could lead to improved stability of the coupled-trajectory dynamics, because it avoids the involvement of "spectator" atoms in the calculation of the G αβ factors. Moreover, Fig. and 10 show that all trajectories remain mostly coupled until 400 fs, and only after 500 fs, the number of lonely trajectories begins to increase significantly.