Hydrogen-bonded phenol–acid clusters studied by vibrational resolved laser spectroscopy and ab initio calculations: II. Acetic acid Original Research Article

Phenol(CH3COOH)n clusters are studied by laser spectroscopy up to n=4 and by ab initio calculations on the Hartree–Fock/6-31G(d,p) level up to n=2. The resonant two-photon ionization (R2PI) spectra do not show any intense signal belonging to phenol(CH3COOH)1 in contrast to the corresponding cluster with formic acid. IR–UV double-resonance and dispersed fluorescence spectra point to a geometry of the n=2 (3) cluster where the phenol molecule acts as proton donor bound to the acetic acid dimer (trimer). Other isomers like a cyclic arrangement as in phenol(HCOOH)2 are discussed.