Here, I is the intensity, E the excitation energy, E i,α and f i,α are the calculated excitation energy and oscillator strength, respectively, for the D 0 → D i transition of snapshot α, σ is a broadening parameter (σ = 0.05 eV in this work), and M is a normalization factor (here, M is chosen to be the maximum intensity of the broadened spectrum in the considered energy interval). For Ama + and Ada + , in the SH dynamics after excitation to the lowest energy band (corresponding to the first intense transition, see below), ten electronic states (the ground state and nine excited states) were taken into account. For Ada-CN + , excitation into the second, higher energy band was also considered, and twelve electronic states (the ground state and eleven excited states) were included in the SH simulations in this case. The trajectories were propagated for 1 ps with a nuclear time step of 0.1 fs and an electronic time step of 1 as. The SH calculations were performed with the MNDO program.