The energy-gap distributions at the hopping time are shown in Figure for S3→S2 and S2→S1 transitions. The hoppings from S3 to S2 (top) are distributed around a relatively large energy gap for both molecules. The distribution follows approximately a Gaussian shape centered around a mean value of 0.47 eV for both 6-and 7-AIH + , respectively, while the standard deviation is 0.13 eV for 6-AIH + and 0.22 eV for 7-isomer. These gap distributions are due to the large energies of the S3/S2 intersections compared to the S3 minimum (see Table ).