Microwave spectrum and large amplitude motion of methanesulfonic acid

Huff, Anna

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https://hdl.handle.net/2142/107418 Copy

Description

Title

Microwave spectrum and large amplitude motion of methanesulfonic acid

Author(s)

Huff, Anna

Contributor(s)

• Leopold, Kenneth R.
• Love, Nathan

Issue Date

2020-06-24

Keyword(s)

Small molecules

Abstract

Microwave spectra have been recorded for methanesulfonic acid (CH$_{3}$SO$_{3}$H) and its –OD isotopologue. No internal rotation of the methyl group was observed, consistent with the calculated barrier of 2.7 kcal/mol. A pair of tunneling states has been observed for both species, however, and is attributed to large amplitude wagging of the hydroxyl hydrogen from one side of the molecule to the other. The predicted barrier to this motion, obtained from M06-2X/6-311++G(3df,3pd) calculations is 0.7 kcal/mol. For CH$_{3}$SO$_{3}$D, the tunneling energy was directly determined to be $\Delta$E = 6471.9269(17) MHz from the measurement of \textit{c}-type spectra. In the case of the parent species, however, transitions displaced by the tunneling energy have not been located and are likely above the maximum frequency accessible by the spectrometer (20 GHz). Thus, the value of $\Delta$E could not be experimentally determined. Nonetheless, a satisfactory fit was obtained for transitions involving J''= 0 and J'' = 1 (nine frequencies for each state). Suggestions for further work at higher frequencies will be presented.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/107418

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Copyright 2020 is held by the Author(s)

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