THE Z-1-CYANO-1,3-BUTADIENE (C5H5N) MILLIMETER-WAVE ROTATIONAL SPECTRUM OF THE GROUND VIBRATIONAL STATE AND FIRST TWO EXCITED VIBRATIONAL STATES (ν19 AND ν27): A MOLECULE OF ASTROCHEMICAL IMPORTANCE

Dorman, P. Matisha

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https://hdl.handle.net/2142/107483 Copy

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Title

THE Z-1-CYANO-1,3-BUTADIENE (C5H5N) MILLIMETER-WAVE ROTATIONAL SPECTRUM OF THE GROUND VIBRATIONAL STATE AND FIRST TWO EXCITED VIBRATIONAL STATES (ν19 AND ν27): A MOLECULE OF ASTROCHEMICAL IMPORTANCE

Author(s)

Dorman, P. Matisha

Contributor(s)

McMahon, Robert J.; Woods, R. Claude; McCarthy, Michael C; Lee, Kelvin ; Hyland, Grace E.; Kougias, Samuel M.; Esselman, Brian J.

Issue Date

25-Jun-20

Keyword(s)

Perturbations, resonances, *-Teller

Abstract

We have synthesized and collected the 135 – 375 GHz rotational spectrum of Z-1-cyano-1,3-butadiene (\chem{C_5H_5N}), an open-chain isomer of pyridine. Its substantial dipole moments ($\mu_a$ = 3.3 D, $\mu_b$ = 2.3 D, B3LYP/6-311+G(2d,p)) make it an attractive species for detection by radioastronomy. We have fit the ground vibrational state to a low-error ($\sigma_{fit}$ = 0.039 MHz), partial octic, distorted-rotor Hamiltonian with 5,500+ distinct transitions in our frequency region, along with 34 hyperfine-resolved microwave transitions collected by the McCarthy Group in both a benzene/\chem{N_2} discharge and in a butadiene/\chem{CH_3CN} discharge. In collaboration, we were able to determine the nuclear hyperfine coupling constants and confirm the presence of Z-1-cyano-1,3-butadiene in the discharge experiments. This analysis provides the fundamental spectroscopic constants needed to support an astronomical search of Z-1-cyano-1,3-butadiene in the interstellar medium. Presently, we are analyzing the two lowest-energy fundamentals, \nub{19} and \nub{27} ($\Delta$E = 7.5 \wn, B3LYP/6-311+G(2d,p)). These fundamental states comprise a Coriolis-coupled dyad exhibiting $\it{a}-$ and $\it{b}$-type coupling, and this presentation will describe the progress of the dyad least-squares fit in the millimeter-wave analysis of Z-1-cyano-1,3-butadiene.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

English

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http://hdl.handle.net/2142/107483

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