The time traces of the populations of the electronic states are shown in Fig. , namely for the diabatic state 2 in the upper panel and for the adiabatic state S 2 in the lower panel. The lower panel clearly shows that, starting in S 2 , the system rapidly decays within 10 fs via the CI in the vicinity of the FC point, with the S 2 population for all methods dropping to ≈ 40%. After that, the methods start to deviate from each other: in TSH-ED (in green), CCTTSH (in red) and CTMQC (in blue), the population of S 2 drops further to ≈ 20% after 30 fs, while in MTE (in orange) it remains just below ≈ 40%. In CTTSH (in lilac), the population P S2 (t) (P) and the fraction of trajectories F S2 (t) (F) yield different results, but this is inconsistency is cured in CCTTSH. After 30 fs, TSH-ED predicts that the population of S 2 decays to less than 10%, while CCTTSH and CTMQC remain close ≈ 20%. Since the ground state is energetically inaccessible, there is effectively no population transfer to S 0 . The LVC Hamiltonian has been parametrized using TDDFT as used for the full dimensional systems and therefore, no couplings between the excited states and the ground state can be calculated reliably. Note that both TSH-ED and CCTTSH predict oscillations in the population of S 2 that are reminiscent of the ab initio "molecular Tully model" DMABN of Ref. [45] and of the multiple consecutive passages through a nonadiabatic region typical of the original Tully model #2. Also, note that our TSH-ED results are slightly different from the results of Ref. [73], which is probably due to the different schemes used to handle frustrated hops and velocity rescaling (in our case, we do not invert the velocity of a trajectory in case of a frustrated hop and we rescale the velocity along the NAC vector).