Structures of hydrogen bond networks formed by a few tens of methanol molecules in the gas phase: size-selective infrared spectroscopy of neutral and protonated methanol clusters

Citation:
Kobayashi, T, Shishido R, Mizuse K, Fujii A, Kuo J-L.  2013.  Structures of hydrogen bond networks formed by a few tens of methanol molecules in the gas phase: size-selective infrared spectroscopy of neutral and protonated methanol clusters. Phys. Chem. Chem. Phys.. 15:9523-9530.: The Royal Society of Chemistry

Abstract:

In this work{,} we report infrared spectra of large neutral and protonated methanol clusters{,} (MeOH)n and H+(MeOH)n{,} in the CH and OH stretching vibrational region in the size range of n = 10-50. The infrared-ultraviolet double resonance scheme combined with mass spectrometry was employed to achieve moderate size selection of the neutral clusters with the addition of a phenol molecule as a chromophore. Infrared dissociation spectroscopy was performed on the protonated methanol clusters by using a tandem quadrupole mass spectrometer to enable the precise size selection of the clusters. While the neutral clusters showed essentially the same spectra in all the observed size range{,} the protonated clusters showed remarkable narrowing of the H-bonded OH stretch band with increasing n. In n [greater-than-or-equal] [similar]30{,} the spectra of the neutral and protonated clusters become almost identical. These spectral features demonstrate that hydrogen bond networks of methanol prefer simple cyclic structures (or {"}bicyclic{"} structures in protonated methanol) and branching of the hydrogen bond networks (side-chain formation) is almost negligible. Implications of the spectra of the clusters are also discussed by comparison with spectra of bulk phases.

Notes:

n/a

Website