The water–methanol complexes. I. A matrix isolation study and an ab   initio calculation on the 1-1 species

The infrared spectrum of the CH3OH:H2O complex isolated in a nitrogen matrix is here reported. The complex is identified through observation of all three internal modes of the water moiety and 10 out of 12 vibrations of the methanol subunit. Several conformers of the CH3OH...OH2 are evidenced through ir photochemical and thermal conversion process, but none corresponds to the reverse CH3HO...HOH structure, with water playing the role of the proton donor. Ab initio calculations on both structures have been performed to obtain their equilibrium geometries and vibrational spectra. They allow to account for the ir spectral changes (frequencies as well as intensities) of the two submolecules interacting through hydrogen bonding within the complex.