title: Far-Infrared Signatures of Hydrogen Bonding in Phenol Derivatives.
abstract: One of the most direct ways to study the intrinsic properties of the hydrogen-bond interaction is by gas-phase far-infrared (far-IR) spectroscopy because the modes involving hydrogen-bond deformation are excited in this spectral region; however, the far-IR regime is often ignored in molecular structure identification due to the absence of strong far-IR light sources and difficulty in assigning the observed modes by quantum chemical calculations. Far-IR/UV ion-dip spectroscopy using the free electron laser FELIX was applied to directly probe the intramolecular hydrogen-bond interaction in a family of phenol derivatives. Three vibrational modes have been identified, which are expected to be diagnostic for the hydrogen-bond strength: hydrogen-bond stretching and hydrogen-bond-donating and -accepting OH torsion vibrations. Their position is evaluated with respect to the hydrogen bond strength, that is, the length of the hydrogen-bonded OH length. This shows that the hydrogen bond stretching frequency is diagnostic for the size of the ring that is closed by the hydrogen bond, while the strength of the hydrogen bond can be determined from the hydrogen-bond-donating OH torsion frequency. The combination of these two normal modes allows the direct probing of intramolecular hydrogen-bond characteristics using conformation-selective far-IR vibrational spectroscopy.
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Daniël J
authors.initials: DJ
authors.lastname: Bakker
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Atze
authors.initials: A
authors.lastname: Peters
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.|University of Gothenburg , Department of Physics, 412 96 Gothenburg, Sweden.
authors.forename: Vasyl
authors.initials: V
authors.lastname: Yatsyna
authors.affiliation: University of Gothenburg , Department of Physics, 412 96 Gothenburg, Sweden.
authors.forename: Vitali
authors.initials: V
authors.lastname: Zhaunerchyk
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Anouk M
authors.initials: AM
authors.lastname: Rijs