Phenol-(ethanol)(1) isomers studied by double-resonance spectroscopy and ab initio calculations

The jet-cooled 1:1 complex of phenol and ethanol was studied by several las er spectroscopic techniques and ab initio calculations at the Hartree-Fock 6-31C(d,p) level. The laser-induced fluorescence (LIF) and mass-selected re sonant two-photon ionization (R2PI) spectra showed that the electronic SI < -- So origin consists of two transitions separated by 2 cm(-1). The dispers ed fluorescence (DF) and IR-UV and W-IR double-resonance spectra reveal tha t these transitions are the electronic origins of two different isomers. Th e ab initio calculations yield three minimum energy structures of anti/gauc he conformers of the ethanol moiety in the hydrogen-bonded cluster. The com parison of the experimental and theoretical results allows an assignment of the spectral features to the calculated rotamer structures.