THE ROTATIONAL SPECTROSCOPY OF 2-FORMYLTHIOPHENE UP TO 750 GHZ IN ITS GROUND AND TWO VIBRATIONALLY EXCITED STATES

Esselman, Brian J.

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Description

Title

THE ROTATIONAL SPECTROSCOPY OF 2-FORMYLTHIOPHENE UP TO 750 GHZ IN ITS GROUND AND TWO VIBRATIONALLY EXCITED STATES

Author(s)

Esselman, Brian J.

Contributor(s)

• McMahon, Robert J.
• Woods, R. Claude
• Nguyen, Ha Vinh Lam

Issue Date

2023-06-21

Keyword(s)

Rotational structure/frequencies

Abstract

The rotational spectrum of 2-formylthiophene (Cs, µₐ = 3.9 D, µb = 2.4 D) has been observed from 2 to 750 GHz and over 8500 transitions have been observed, measured, and least-squares fit for the ground vibrational state. The extensive frequency coverage allowed measurement of transitions up to J = 180 and Kₐ = 72. Spectroscopic constants have been obtained for a complete sextic distorted-rotor A- and S-reduced Hamiltonians, in the Iʳ representation. The first two vibrationally excited states of 2-formylthiophene are the torsional mode (ν₂₇, A′′, 122 cm−¹) and the in-plane C-C-O bend (ν₁₉, A′, 173 cm−¹) of the formyl group. These two vibrationally excited states exhibit rotational transitions with frequencies perturbed by a- and b-axis Coriolis coupling despite an energy gap of nearly 50 cm−¹. Rotational transitions for the first two vibrationally excited states have been assigned, measured, and least-squares fit to a two-state Hamiltonian, which will provide an accurate and precise energy gap and Coriolis-coupling constants for these two modes.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122336

DOI

https://doi.org/10.15278/isms.2023.6875

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