Submillimeter-wave spectroscopy of the CH$_3$O radical

Fuente: arXiv
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Main Authors: Spaniol, Jean-Thibaut, Chitarra, Olivia, Pirali, Olivier, Martin-Drumel, Marie-Aline, Müller, Holger S. P.
Format: Preprint
Published: 2024
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_version_ 1866909615513403392
author Spaniol, Jean-Thibaut
Chitarra, Olivia
Pirali, Olivier
Martin-Drumel, Marie-Aline
Müller, Holger S. P.
author_facet Spaniol, Jean-Thibaut
Chitarra, Olivia
Pirali, Olivier
Martin-Drumel, Marie-Aline
Müller, Holger S. P.
contents The methoxy radical, CH$_3$O, has long been studied experimentally and theoretically by spectroscopists because it displays a weak Jahn-Teller effect in its electronic ground state, combined with a strong spin-orbit interaction. In this work, we report an extension of the measurement of the pure rotational spectrum of the radical in its vibrational ground state in the submillimeter-wave region (350$-$860 GHz). CH$_3$O was produced by H-abstraction from methanol using F-atoms, and its spectrum was probed in absorption using an association of source-frequency modulation and Zeeman modulation spectroscopy. All the observed transitions together with available literature data in $v = 0$ were combined and fit using an effective Hamiltonian allowing to reproduce the data at their experimental accuracy. The newly measured transitions involve significantly higher frequencies and rotational quantum numbers than those reported in the literature ($f < 860$ GHz and $N \leq 15$ instead of 272 GHz and 7, respectively) which results in significant improvements in the spectroscopic parameters determination. The present model is well constrained and allows a reliable calculation of the rotational spectrum of the radical over the entire microwave to submillimeter-wave domain. It can be used with confidence for future searches of CH$_3$O in the laboratory and the interstellar medium.
format Preprint
id arxiv_https___arxiv_org_abs_2412_20990
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Submillimeter-wave spectroscopy of the CH$_3$O radical
Spaniol, Jean-Thibaut
Chitarra, Olivia
Pirali, Olivier
Martin-Drumel, Marie-Aline
Müller, Holger S. P.
Astrophysics of Galaxies
Solar and Stellar Astrophysics
Atomic Physics
Chemical Physics
The methoxy radical, CH$_3$O, has long been studied experimentally and theoretically by spectroscopists because it displays a weak Jahn-Teller effect in its electronic ground state, combined with a strong spin-orbit interaction. In this work, we report an extension of the measurement of the pure rotational spectrum of the radical in its vibrational ground state in the submillimeter-wave region (350$-$860 GHz). CH$_3$O was produced by H-abstraction from methanol using F-atoms, and its spectrum was probed in absorption using an association of source-frequency modulation and Zeeman modulation spectroscopy. All the observed transitions together with available literature data in $v = 0$ were combined and fit using an effective Hamiltonian allowing to reproduce the data at their experimental accuracy. The newly measured transitions involve significantly higher frequencies and rotational quantum numbers than those reported in the literature ($f < 860$ GHz and $N \leq 15$ instead of 272 GHz and 7, respectively) which results in significant improvements in the spectroscopic parameters determination. The present model is well constrained and allows a reliable calculation of the rotational spectrum of the radical over the entire microwave to submillimeter-wave domain. It can be used with confidence for future searches of CH$_3$O in the laboratory and the interstellar medium.
title Submillimeter-wave spectroscopy of the CH$_3$O radical
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
Atomic Physics
Chemical Physics
url https://arxiv.org/abs/2412.20990