ROTATIONAL SPECTROSCOPY OF SYN AND ANTI-CLINAL PENTA-3,4-DIENENITRILE FROM 130-375 GHz

Orr, Vanessa L.

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https://hdl.handle.net/2142/104419 Copy

Description

Title

ROTATIONAL SPECTROSCOPY OF SYN AND ANTI-CLINAL PENTA-3,4-DIENENITRILE FROM 130-375 GHz

Author(s)

Orr, Vanessa L.

Contributor(s)

McMahon, Robert J.; Woods, R. Claude; Kougias, Samuel M.; Owen, Andrew N; Esselman, Brian J.

Issue Date

2019-06-20

Keyword(s)

Rotational structure/frequencies

Abstract

Penta-3,4-dienenitrile, (P34DN, \chem{H_2C}=\chem{C}=\chem{CHCH_2CN}), is an intriguing target for detection in the interstellar medium and the atmosphere of Titan because of its structural similarity to known interstellar molecules and because it is a constitutional isomer of the simple aromatic compound, pyridine (\textit{c}-\chem{C_5H_5N}). P34DN has recently been synthesized in our group and its millimeter-wave spectrum has been collected from $\sim$130-375 GHz. Computational studies reveal that P34DN has two stable conformers linked by the internal rotation of the \chem{-CH_2CN} group and separated by $\textless{1}$ kcal/mol. The internal rotation is the lowest fundamental, $\nu_{27}$, in both conformers. Over 800 distinct rotational transitions of the ground vibrational state of the \textit{syn} conformer ($\textit{C}_{s}$, $\mu_{a}=1.7$ D, $\mu_{b}=3.1$ D, CCSD(T)/cc-pVTZ) have been least-squares fit to a single-state centrifugally distorted rotor model using Kisiel’s ASFIT, and analysis of this ground state is ongoing. The \textit{anti-clinal} conformer of P34DN has $\textit{C}_1$ symmetry ($\mu_{a}=3.4$ D, $\mu_{b}=1.9$ D, $\mu_{c}=0.6$ D, CCSD(T)/cc-pVTZ). Rotational transitions for the ground state and the vibrational states $\nu_{27}$, $2\nu_{27}$, $3\nu_{27}$, and $4\nu_{27}$ have been identified. Clear evidence of strong Coriolis coupling between the ground state and $\nu_{27}$ ($\sim{52}$ $cm^{-1}$) has been observed, primarily between $\textit{K}=18$ of the ground state and $\textit{K}=14$ of the excited state. Coupling is also observed between the v = 1 and v = 2 of $\nu_{27}$. This presentation will discuss the current analysis of the coupling between the ground state and $\nu_{27}$ v = 1 and the current status of their coupled least-squares fit using Pickett’s SPFIT program.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/104419

DOI

10.15278/isms.2019.RI07

Copyright and License Information

Copyright 2019 Vanessa L. Orr

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