of trajectories along the normal mode 24 in Fig. . The color coding is similar as in Fig. , but here red indicates the trajectories in S 1 and blue in S 0 . The dynamics for approximately the first 20 fs is sketched in the inset of Fig. . Starting in S 1 , the wavepacket arrives at the sloped CI (≈ 8 fs) and switches nearly completely to S 0 . After being reflected by the potential wall (≈ 11 fs), the wavepacket passes through the CI again (≈ 14 fs) and branches into two wavepackets, one remaining in S 0 and one transferring to S 1 . This process repeats, since the wavepackets are reflected by the opposite potential wall, which results to a stepwise population transfer. Both methods CTMQC and CCTTSH reproduce this dynamics very well and in particular the branching in different states. However, CTMQC trajectories are more spread, and this can be traced back to two effects. First, for example at ≈ 30 fs, when the turning point close to the CI is reached a second time, one can see high energy trajectories, that, instead of passing the CI to S 0 , stay on S 1 and get reflected much later. Nonetheless, only very few trajectories in fulvene undergo this process. To make this effect more apparent, we highlighted one of those trajectories by decreasing its transparency. Second, it can be seen that in general, the trajectories increasingly spread in time. Both effects result in a "classical dephasing" of the trajectories and thus in dispersion in both position and momentum space.