Phenol−(Ethanol)₁ Isomers Studied by Double-Resonance Spectroscopy and ab Initio Calculations

Abstract

The jet-cooled 1:1 complex of phenol and ethanol was studied by several laser spectroscopic techniques and ab initio calculations at the Hartree−Fock 6-31G(d,p) level. The laser-induced fluorescence (LIF) and mass-selected resonant two-photon ionization (R2PI) spectra showed that the electronic S1 ← S0 origin consists of two transitions separated by 2 cm-1. The dispersed fluorescence (DF) and IR−UV and UV−IR double-resonance spectra reveal that these transitions are the electronic origins of two different isomers. The ab initio calculations yield three minimum energy structures of anti/gauche conformers of the ethanol moiety in the hydrogen-bonded cluster. The comparison of the experimental and theoretical results allows an assignment of the spectral features to the calculated rotamer structures.