The rotational spectra of benzyl alcohol and of its OD isotopologue have been assigned and measured in a supersonic expansion, either with pulsed-jet Fourier transform microwave or free jet absorption millimeter wave spectroscopy. The spectrum is consistent with a gauche conformation of the oxygen atom, characterized by a θ (OC7-C1C2) dihedral angle of approximately 55°. Such a configuration is 4-fold degenerate, corresponding to minima with θ ≈ (60°, (120°. The four equivalent minima are separated by two kinds of barrier, corresponding to θ ) (90°, and 0 or 180°. Only the θ ) (90° barriers are low enough to generate a tunneling splitting, which has been measured in a spectrum strongly perturbed by tunneling interactions. The observed splittings diminish considerably upon deuterium substitution. The tunneling splittings are consistent with a barrier about 280 cm-1 and high level ab initio calculations predicting a 320 cm-1 barrier.
Titolo: | Rotational Spectrum, Tunneling Motions, and Potential Barriers of Benzyl Alcohol |
Autore/i: | K. A. Utzat; R. K. Bohn; J. A. Montgomery J.r.; H. Harvey Michels; CAMINATI, WALTHER |
Autore/i Unibo: | |
Anno: | 2010 |
Rivista: | |
Digital Object Identifier (DOI): | 10.1021/jp102903p |
Abstract: | The rotational spectra of benzyl alcohol and of its OD isotopologue have been assigned and measured in a supersonic expansion, either with pulsed-jet Fourier transform microwave or free jet absorption millimeter wave spectroscopy. The spectrum is consistent with a gauche conformation of the oxygen atom, characterized by a θ (OC7-C1C2) dihedral angle of approximately 55°. Such a configuration is 4-fold degenerate, corresponding to minima with θ ≈ (60°, (120°. The four equivalent minima are separated by two kinds of barrier, corresponding to θ ) (90°, and 0 or 180°. Only the θ ) (90° barriers are low enough to generate a tunneling splitting, which has been measured in a spectrum strongly perturbed by tunneling interactions. The observed splittings diminish considerably upon deuterium substitution. The tunneling splittings are consistent with a barrier about 280 cm-1 and high level ab initio calculations predicting a 320 cm-1 barrier. |
Data prodotto definitivo in UGOV: | 2011-01-28 18:34:57 |
Appare nelle tipologie: | 1.01 Articolo in rivista |