Laboratory Rotational Spectra of Cyanocyclohexane and Its Siblings (1- and 4-Cyanocyclohexene) Using a Compact CP-FTMW Spectrometer for Interstellar Detection
Name
2504.13686v1.pdf
Description
Accepted version
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9.47 MB
Format
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Author(s)
Wenzel, Gabi
Holdren, Martin S
Stewart, D Archie
Toru Shay, Hannah
Byrne, Alex N
Xue, Ci
McGuire, Brett A
Date Issued
April 24, 2025
Journal
The Journal of Physical Chemistry A
Publisher
American Chemical Society
Citation
Gabi Wenzel, Martin S. Holdren, D. Archie Stewart, Hannah Toru Shay, Alex N. Byrne, Ci Xue, Brett A. McGuire; Laboratory Rotational Spectra of Cyanocyclohexane and Its Siblings (1- and 4‑Cyanocyclohexene) Using a Compact CP-FTMW Spectrometer for Interstellar Detection. J. Phys. Chem. A 8 May 2025; 129 (18): 3986–4001.
Version
Author's final manuscript
Abstract
Chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy is a versatile technique to record broadband gas-phase rotational spectra, enabling detailed investigations of molecular structure, dynamics, and hyperfine interactions. Here, we present the development and application of a CP-FTMW spectrometer operating in the 6.5-18 GHz frequency range, studying cyanocyclohexane, 1-cyanocyclohexene, and 4-cyanocyclohexene using a heated pulsed supersonic expansion source. The dynamic range, experimental resolution, and high sensitivity enable observation of multiple conformers, precise measurements of hyperfine splitting arising from nuclear quadrupole coupling due to the nitrogen atom in the cyano group, as well as the observation of singly 13C- and 15N-substituted isotopic isomers in natural abundance. Using the latter, precise structures for the molecules are derived. The accurate rotational spectra enabled a search for these species toward the dark, cold molecular cloud TMC-1; no signals are found, and we discuss the implications of derived upper limits on the interstellar chemistry of the cyanocyclohexane family.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.1021/acs.jpca.5c00980
