Theoretical and experimental studies on the hydroquinone–argon 1:1 complex: A blueshifted O–H–Ar bond

Abstract

Resonantly enhanced multiphoton ionization (REMPI), hole burning studies, as well as ab initio calculations on the hydroquinone–argon 1:1 complex, are presented in this paper. The REMPI spectrum displayed features due to the complex up to ∼1250 cm−1, which is unusually high for such complexes. The complex, like the monomer, was found to exist in both cis- and trans- conformational forms. Ab initio calculations carried out at the MP2/6-31+G* level for the S0 state of the complex yielded pi-bonded as well as H-bonded structures. The experimentally observed conformers are assigned pi-bonded structures. The high stability of the complex was attributed to slow vibrational predissociation rate constants due to the existence of multiple minima in the potential energy surface. Calculations on the S0 state of the H-bonded aminophenol–argon 1:1 complex are also reported and compared with the corresponding hydroquinone–argon structures. The H-bonded structures were found to possess blueshifted H bonds.