Observation of Tunneling States Within the Two Conformations of Hydroxyl Gauche, Methyl Asymmetric CH2DCH2OH

Published

October 1, 1997

Author(s)

R D. Suenram, Francis J. Lovas, C R. Quade, C F. Su

Abstract

Fourier Transform Microwave (FTMW) Spectroscopy has been used to observe and resolve the 60 kHz tunneling splitting between the symmetric and antisymmetric substates of conformations I and II for hydroxyl gauche, methyl asymmetric CH₂DCH₂OH. Conformation has the hydroxyl H and Methyl D on the same side of the molecular plane whereas conformation II has them on the opposite sides. The determination of the small energy difference between these two conformers leads to an improved value of V_s1s2, [the potential energy coefficient that localizes the molecule into conformations I and II] of 4.8[5] cm^-1. Further, the relative intensities of the spectra show that conformation II is lower in energy than conformation I. Analysis of the quadruple splittings of the a-type 1₀₁-0₀₀ transitions determines values for eQq_aa that range from -87 KHz to -98 KHz for both hydroxyl conformations with the methyl group asymmetric and +84 kHz to + 102 kHz for both hydroxyl conformations with the methyl group symmetric.

Citation

Journal Molecular Spectroscopy

Volume

188

Pub Type

Journals

Keywords

ethanol, ethyl alcohol, microwave spectroscopy, microwave spectrum, rotational spectrum, rotational tunneling

Citation

Suenram, R. , Lovas, F. , Quade, C. and Su, C. (1997), Observation of Tunneling States Within the Two Conformations of Hydroxyl Gauche, Methyl Asymmetric CH₂DCH₂OH, Journal Molecular Spectroscopy (Accessed October 18, 2025)