Five hundred initial conditions were sampled from a harmonic oscillator Wigner distribution using the ground-state geometry and normal modes. The absorption spectra into eight excited states for both species were simulated for these initial conditions (see Figure in the SI). For 6-AIH + , we have chosen 60 initial conditions in the energy window 5.5  0.2 eV to start trajectories in the S3 state (ESI, SI-1). For 7-AIH + , we selected 84 initial conditions in the same energy window, to start trajectories also in S3.