Fig. provides a slightly more challenging system: the methyliminium cation (CH 2 NH 2 + ). This model is very similar to ethylene in the sense that a CI is generated by the changing H-C-N-H dihedral angle. As such, the benchmark AIMS results suggest that the population dynamics have very similar features as the ethylene dynamics; however, a recurrence/shoulder in the population of the S 1 state appears around 25-30 fs. For this system, all methods, including augmented FSSH (A-FSSH) and the mapping approaches, overestimate the initial population transfer to the ground state around 10 fs. Following this, all approaches seem to provide a plateau in the population of the S 1 state, but only A-FSSH, γ-SQC-∆, and spin-PLDM are able to showcase a visible recurrence in the S 1 population. Throughout the entire dynamics, A-FSSH seems to capture all of the features found in the AIMS result, with spin-PLDM and γ-SQC-∆ close behind, but both of which overestimate the S 1 population (or rather underestimate the population transfer rate to the ground state) at long times (more than 50 fs). For this model, it is clear that spin-LSC performs worse than the other models while A-FSSH performs well compared to the AIMS result.