ROTATIONAL SPECTRUM AND INTERSTELLAR DETECTION OF THE FIRST TORSIONALLY EXCITED STATE OF METHYLAMINE

Kleiner, Isabelle

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https://hdl.handle.net/2142/122316 Copy

Description

Title

ROTATIONAL SPECTRUM AND INTERSTELLAR DETECTION OF THE FIRST TORSIONALLY EXCITED STATE OF METHYLAMINE

Author(s)

Kleiner, Isabelle

Contributor(s)

• Kreglewski, Marek
• Gulaczyk, Iwona
• Alekseev, E. A.
• Ilyushin, V.
• Belloche, Arnaud
• Motiyenko, R. A.
• Gyawali, Prakash

Issue Date

2023-06-20

Keyword(s)

Astronomy

Abstract

Methylamine (CH₃NH₂) was first detected in the interstellar medium (ISM) toward Sgr B2 almost 50 years ago by observation of its vₜ = 0 rotational transitionsᵃ. Methylamine exhibits two large amplitude motions, methyl torsion and amine wagging, that complicate the spectral analysis especially in excited vibration states. This work aims to study experimentally and theoretically the terahertz rotational spectrum of methylamine to provide a reliable basis for the ISM detection of rotational transitions in vₜ = 1 state. The terahertz spectrum of methylamine was measured from 150 to 1520 GHz with the Lille fast scan spectrometer. Using a new “hybrid” Hamiltonian model, we were able to fit accurately the rotational spectrum of the vₜ= 1 state of methylamine including the analysis of the nuclear quadrupole hyperfine structure. The results of this spectroscopic analysis allowed us to search for rotational transitions of methylamine in its first torsionally excited state toward the high-mass star forming region Sgr B2(N) that was the target of the imaging spectral line survey ReMoCA performed with the Atacama Large Millimeter/submillimeter Array (ALMA). We report the first interstellar detection of methylamine in its vₜ = 1 state on the basis of this interferometric data set.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122316

DOI

https://doi.org/10.15278/isms.2023.6846

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