"Millimeter-wave Spectroscopy Of The Excited Vibrational States Of Thiophene (<span Class=""roman"">c</span>_{<span Class=""roman"">4</span>}<span Class=""roman"">h</span>_{<span Class=""roman"">4</span>}<span Class=""roman"">s</span>)"

Esselman, Brian J.

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https://hdl.handle.net/2142/111452 Copy

Description

Title

"Millimeter-wave Spectroscopy Of The Excited Vibrational States Of Thiophene (c₄h₄s)"

Author(s)

Esselman, Brian J.

Contributor(s)

• McMahon, Robert J.
• Woods, R. Claude
• Kobayashi, Kaori
• Ichikawa, Yotaro
• Orr, Vanessa L.

Issue Date

2021-06-24

Keyword(s)

Rotational structure/frequencies

Abstract

Thiophene is a five-membered, aromatic heterocycle with $\textit{C}_{2v}$ symmetry and a moderate dipole (\chem{C_4H_4S}, $\mu_a$ = 0.55 D). A number of fundamental states of thiophene had previously been investigated through ro-vibrational studies in the infrared, but pure rotational spectroscopy had not extended beyond the ground state. We have measured and assigned transitions for 19 excited states by rotational spectroscopy, three of which are the IR inactive, $\textit{A}_2$ symmetry states, and several of which are overtones or combination states. The new mm-wave data (40 - 360 GHz) and the previously published high resolution IR data are combined in a global least-squares fit. The interactions between the states permit the determination of several precise fundamental frequencies beyond those previously directly measured by high-resolution IR. The vibrationally excited states treated here are connected by a Fermi interaction and complex set of multiple Coriolis couplings, many of which are determined by the global fit. Several of these states may be treated as isolated vibrational states, but other states are involved in a pentad, a triad, and at least three dyads.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111452

DOI

10.15278/isms.2021.RA02

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