Hydrogen Bonding in Alcohol Clusters:  A Comparative Study by Infrared Cavity Ringdown Laser Absorption Spectroscopy

Infrared cavity ringdown laser absorption spectroscopy has been used to study the O−H stretching vibrations of jet-cooled ethanol and butanol clusters. Three bonded O−H stretches were attributed to the ethanol dimer, indicating the presence of more than one conformer in the molecular beam. One unresolved feature was measured for both the trimer and tetramer. To facilitate spectral assignment, the vibrational frequencies and intensities have been calculated for the ethanol dimer using second-order Moller−Plesset perturbation theory. Three bonded O−H stretches have also been measured for the butanol dimer, suggesting that more than one conformer is present in the molecular beam. Vibrational bands were also detected for the butanol trimer and tetramer.