THE ROTATIONAL SPECTRA OF 2-CYANOPYRIMIDINE (C5H3N3) AND 2-CYANOPYRAZINE (C5H3N3): VIBRATIONAL GROUND STATES AND DYAD OF LOWEST-ENERGY VIBRATIONALLY EXCITED STATES

Smith, Houston H.

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https://hdl.handle.net/2142/116657 Copy

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Title

THE ROTATIONAL SPECTRA OF 2-CYANOPYRIMIDINE (C5H3N3) AND 2-CYANOPYRAZINE (C5H3N3): VIBRATIONAL GROUND STATES AND DYAD OF LOWEST-ENERGY VIBRATIONALLY EXCITED STATES

Author(s)

Smith, Houston H.

Contributor(s)

McMahon, Robert J.; Woods, R. Claude; Zdanovskaia, Maria ; Esselman, Brian J.

Issue Date

2022-06-21

Keyword(s)

Comparing theory and experiment

Abstract

2-Cyanopyrimidine and 2-cyanopyrazine are heterocyclic analogs of the known interstellar molecule benzonitrile. They are attractive molecules for interstellar detection \textit{via} radioastronomy because they have substantial dipole moments ($\mu$$_{a}$ = 6.47 D and $\mu$$_{a}$ = 4.22 D, respectively) and could serve as tracer molecules for both pyrimidine and pyrazine. In the present work, we analyzed and assigned the rotational spectra of 2-cyanopyrimidine (\chem{C_5H_3N_3}) and 2-cyanopyrazine (\chem{C_5H_3N_3}) for the first time. From 130 – 500 GHz, the vibrational ground state transitions of each molecule have been least-squares fit to partial octic, distorted-rotor Hamiltonian with each fit containing several thousand transitions. The resulting spectroscopic constants are sufficient for radioastronomical searches for these molecules. Further similar to benzonitrile, the two lowest-energy vibrationally excited states form Coriolis coupled dyads for both 2-cyanopyrimidine and 2-cyanopyrazine. Several thousand transitions of each vibrationally excited state have been assigned and analyzed with a partial octic, distorted-rotor Hamiltonian with a- and/or b-axis Coriolis coupling. The complete analysis of these states is expected to yield a highly precise energy separation between these vibrationally excited states and allow for an interesting comparison to the analogous dyads of benzonitrile and the cyanopyridines.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116657

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