Figure 6

A schematic illustration of the ionization mechanism. The 1^st, 2^nd, 3^rd, and 4^th peaks are generated from the planar geometry which are connected to different ion vibrational states. The 5^th, 6^th, 7^th, and 8^th peaks are assigned to photoionization from the nonplanar minimum via the resonances with the 3 s and 3p Rydberg states.