Isomerization reaction in high-n Rydberg states of phenol–Ar/Kr clusters measured by autoionization detected infrared spectroscopy

Infrared (IR) spectra of phenol–Ar/Kr in high-n Rydberg states converging to the cation ground state were measured by autoionization detected IR (ADIR) spectroscopy. Although the clusters were excited via the S1 state of the π-bound structures, the ADIR spectra exhibit free and hydrogen-bonded OH stretching vibrations (νOH). Thus, similar to direct photoionization, excitation into high-n Rydberg states causes the π–H site switching of the rare gas ligand from the aromatic ring to the OH group. This result demonstrates that the Rydberg electron is insensitive to the dynamics in the ion core.