Chirped-pulse Fourier-transform millimeter-wave rotational spectroscopy of furan in its v10 and v13 excited vibrational states

Mishra, Piyush; Hull, Alexander; Barnum, Timothy J.; McGuire, Brett A.; Field, Robert W.

doi:10.1016/j.jms.2022.111686

Cited by 2 publications

(3 citation statements)

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“…Relative populations were obtained after power correction and integration of intensity over the resolved hyperfine structure. The rotational transitions were Doppler broadened, with an observed full width at half-maximum of 0.8 MHz …”

Section: Methodsmentioning

confidence: 99%

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Signatures of Reaction Mechanisms Encoded in the Vibrational Population Distribution of Small-Molecule Products: Photodissociation of Symmetric-Triazine Using 266 nm Radiation

Mishra

Hull

Coy

et al. 2023

J. Phys. Chem. Lett.

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We utilize rotationally resolved Chirped-Pulse Fourier Transform millimeter-wave spectroscopy to study photodissociation dynamics of 1,3,5-Triazine (symmetric-Triazine) to form 3 HCN molecules. The state-specific vibrational population distribution (VPD) of the photofragments contains mechanistic details of the reaction. This photodissociation is performed using 266 nm radiation transverse to a seeded supersonic jet. The vibrational cooling ineff iciency in the jet preserves the VPD of the photofragments, while rotational cooling enhances the signal of low-J pure-rotational transitions. The multiplexed nature of the spectrometer enables simultaneous sampling of several "vibrational satellites" of the J = 1 ← 0 transition of HCN. Excited state populations along the HCN bend (v 2 ) and CN stretch (v 3 ) modes are observed, which show ≥3.2% vibrational excitation of the photofragments. Observation of an at least bimodal VPD, along the even-v states of v 2 , implies an asymmetric partitioning of vibrational energy among the HCN photofragments. This suggests a sequential dissociation mechanism of symmetric-Triazine initiated by 266 nm radiation.

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Section: Methodsmentioning

confidence: 99%

“…The rotational transitions were Doppler broadened, with an observed full width at half-maximum of 0.8 MHz. 39 ■ ASSOCIATED CONTENT * sı Supporting Information…”

Section: T H Imentioning

confidence: 99%

Signatures of Reaction Mechanisms Encoded in the Vibrational Population Distribution of Small-Molecule Products: Photodissociation of Symmetric-Triazine Using 266 nm Radiation

Mishra

Hull

Coy

et al. 2023

J. Phys. Chem. Lett.

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“…Despite their prevalence in natural products, aromatic heterocycles with a permanent dipole moment have eluded all radioastronomical searches. − The feasibility of radioastronomical detection of a molecule depends upon its population in the source of interest, the intensity of its rotational transitions due to its dipole moment, and the quality of the measurements of its laboratory transition frequencies. The rotational spectrum − and high-resolution infrared spectrum of furan − have been well investigated, but, despite the available, high-quality laboratory spectra, this important heterocycle has eluded detection in the interstellar medium (ISM). ,, Furan ( c -C 4 H 4 O, C 2 v , κ = 0.916) is a near-oblate aromatic heterocycle with an a -axis dipole moment (μ a = 0.661(6) D) . While its relatively weak permanent dipole moment makes the detection of furan more challenging, molecules with similar dipoles have been detected in extraterrestrial sources, e .…”

Section: Introductionmentioning

confidence: 99%

Millimeter-Wave and High-Resolution Infrared Spectroscopy of 2-Furonitrile─A Highly Polar Substituted Furan

et al. 2023

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The rotational spectrum of 2-furonitrile (2-cyanofuran) has been obtained from 140 to 750 GHz, capturing its most intense rotational transitions at ambient temperature. 2-Furonitrile is one of two isomeric cyano-substituted furan derivatives, both of which possess a substantial dipole moment due to the cyano group. The large dipole of 2-furonitrile allowed over 10 000 rotational transitions of its ground vibrational state to be observed and least-squares fit to partial octic, A-and S-reduced Hamiltonians with low statistical uncertainty (σ fit = 40 kHz). The high-resolution infrared spectrum, obtained at the Canadian Light Source, allowed for accurate and precise determination of the band origins of its three lowest-energy fundamental modes (ν 24 , ν 17 , and ν 23 ). Similar to other cyanoarenes, the first two fundamental modes (ν 24, A″, and ν 17 , A′, for 2-furonitrile) form an a-and b-axis Coriolis-coupled dyad. More than 7000 transitions from each of these fundamental states were fit to an octic A-reduced Hamiltonian (σ fit = 48 kHz), and the combined spectroscopic analysis determines fundamental energies of 160.1645522 (26) cm −1 and 171.9436561 (25) cm −1 for ν 24 and ν 17 , respectively. The least-squares fitting of this Coriolis-coupled dyad required 11 coupling terms,J , and F ac K . Using both the rotational and high-resolution infrared spectra, a preliminary least-squares fit was obtained for ν 23 , providing its band origin of 456.7912716 (57) cm −1 . The transition frequencies and spectroscopic constants provided in this work, when combined with theoretical or experimental nuclear quadrupole coupling constants, will provide the foundation for future radioastronomical searches for 2-furonitrile across the frequency range of currently available radiotelescopes.

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Chirped-pulse Fourier-transform millimeter-wave rotational spectroscopy of furan in its v10 and v13 excited vibrational states

Cited by 2 publications

References 57 publications

Signatures of Reaction Mechanisms Encoded in the Vibrational Population Distribution of Small-Molecule Products: Photodissociation of Symmetric-Triazine Using 266 nm Radiation

Signatures of Reaction Mechanisms Encoded in the Vibrational Population Distribution of Small-Molecule Products: Photodissociation of Symmetric-Triazine Using 266 nm Radiation

Millimeter-Wave and High-Resolution Infrared Spectroscopy of 2-Furonitrile─A Highly Polar Substituted Furan

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