Millimeter-wave Spectrum Of The Lowest Energy, Vibrationally Excited Coupled Dyad Of S-trans-z-1-cyano-1,3-butadiene

Dorman, P. Matisha

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https://hdl.handle.net/2142/116505 Copy

Description

Title

Millimeter-wave Spectrum Of The Lowest Energy, Vibrationally Excited Coupled Dyad Of S-trans-z-1-cyano-1,3-butadiene

Author(s)

Dorman, P. Matisha

Contributor(s)

• Woods, R. Claude
• McMahon, Robert J.
• Esselman, Brian J.

Issue Date

2022-06-21

Keyword(s)

Comparing theory and experiment

Abstract

Recently, the ground state spectroscopic constants of three cyanobutadiene isomers (\chem{C_5H_5N}) were reported as plausible targets for detection in the interstellar medium.$^{1}$ Many hundreds of transitions were collected in the 130 – 375 GHz range for each isomer, but \textit{s}-\textit{trans}-\textit{Z}-1-cyano-1,3-butadiene is the only isomer with an isolated ground state. \textit{s}-\textit{trans}-\textit{Z}-1-Cyano-1,3-butadiene ($\mu_{a}$ = 3.6 D, $\mu_{b}$ = 2.3 D, MP2/6-311+G(2d,p) is a prolate ($\kappa$ = $-0.91$), asymmetric top with \textit{C}$_s$ symmetry, and its ground state was fit to a partial octic, distorted rotor Hamiltonian model with over 5500 distinct transitions. The lowest-energy vibrationally excited state (\nub{19}, \textit{B}$_1$) is predicted to be 129 \wn higher in energy than the ground state and is close in energy to the second-lowest energy vibrationally excited state (\nub{27}, \textit{B}$_2$, 135 \wn, MP2/6-311+G(2d,p)). These states form a Coriolis coupled dyad with intense coupling along the \textit{a}- and \textit{b}- principal axes causing the formation of sharp local resonances hundreds of MHz away from their unperturbed predicted frequencies. This presentation will detail the effects of strong Coriolis coupling in a dyad of vibrational states $<$ 6 \wn apart and the strategies used to assign and least-squares fit these transitions. 1. Zdanovskaia, M. A.; Dorman, P. M.; Orr, V. L.; Owen, A. N.; Kougias, S. M.; Esselman, B. J.; Woods, R. C.; McMahon, R. J. Rotational Spectra of Three Cyanobutadiene Isomers (\chem{C_5H_5N}) of Relevance to Astrochemistry and Other Harsh Reaction Environments. \textit{J. Am Chem. Soc.} \textbf{2021}, \textit{143}, 9551-9564.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116505

DOI

https://doi.org/10.15278/isms.2022.TF05

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Copyright 2022 held by the authors

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