Isomer-Selective Spectroscopy and Dynamics of Phenol–Ar_n (n ≤ 5) Clusters

Abstract

Structures and ionization-induced solvation dynamics of phenol–(argon) n clusters, PhOH–Ar n (n ≤ 5), were studied by using a variety of isomer-selective photoionization and vibrational spectroscopic techniques. Several higher-energy isomers were found and assigned for the first time by systematically controlling the experimental conditions of the supersonic expansion. This behavior is also confirmed for the PhOH–Kr2 cluster. Solvation structures are elucidated by evaluating systematic shifts in the S1 ← S0 origin and ionization energies obtained by resonance-enhanced photoionization, in addition to the OH stretching frequency obtained by IR photodissociation. Isomer-selective picosecond time-resolved IR spectroscopy for the n = 2 clusters revealed that the dynamics for the ionization-induced intermolecular π → H site-switching reaction strongly depends on the initial isomeric structure. In particular, the reaction time for the (1|1) isomer is 7 ps, while that for (2|0) is <3 ps. This difference shows that the switching time is determined by the distance of the reaction coordinate between the initial π-site and the final OH-site.

Hydration Rearrangement in the 4‐Aminobenzonitrile−(H2O)2 Cluster Induced by Photoionization: The Effect of Solvent‐Solvent Interactions

“…Hence, to achieve a more complete molecular level understanding of solvation rearrangement dynamics, studies on multiply hydrated clusters featuring also solvent-solvent interactions need to be considered. Previous studies of aromatic molecules solvated by rare gas (Rg) atoms [42][43][44][45][46][47][48][49] reveal that the RgÀ Rg interaction is too weak relative to the cation-Rg interaction to play a major role on the energetics of the reaction. However, the reaction mechanism and timescale are strongly affected by type and number of Rg atoms.…”