# $talk$ - Investigation of pure rotational spectroscopy of ethynylbenzonitrile isomers using chirped-pulse W-band spectroscopy

### Abstract

Simple aromatic molecules may be precursors for polycyclic aromatic hydrocarbons in space, and some of the simplest ones are now detected in the earliest stages of star formation [1]. Evidence of benzonitrile (C6H5-CN) in the interstellar medium [2] questions the presence of related aromatic nitriles and their ring-chain derivatives. In light of previous work [3] on phenylpropiolonitrile (C6H5-C3N), we are investigating, by laboratory high-resolution studies, its ethynylbenzonitrile (HCC-C6H4-CN) derivatives where a -CN and a -CCH groups lie in ortho (2-ETB), meta (3-ETB) or para (4-ETB) positions.

The pure rotational spectrum of these compounds has been recorded at room temperature in the millimeter-wave domain using a chirped-pulse W-band (75–110 GHz) spectrometer. To facilitate spectral assignments, quantum chemical calculations have been performed using density functional theory at the $\omega$B97X-D/cc-pVQZ level of theory (geometry optimization, harmonic frequencies).

We will report a description of the experimental set-up and of our assignment procedure.

[1] A.Burkhardt et al., Nature Astronomy 5, 181-187 (2021)

[2] McGuire et al., Science 359, 202-205 (2018)

[3] Z.Buchanan et al., Journal of Molecular Spectroscopy 377, 111425 (2021)

Date
Jun 21, 2021 — Jun 25, 2021
Location
Virtual Conference
University of Illinois, USA
##### Jean-Thibaut Spaniol
###### Master Student

Master 2 student with a passion for teaching that overpassed his love for spectroscopy.

##### Olivier Pirali
###### Director of Research

My research interests includes high resolution molecular spectroscopy, laboratory astrophysics, and THz generation.

##### Marie-Aline Martin-Drumel
###### Researcher

My research interests focus on molecular spectroscopy of stable molecules and reactive species, and its applications for astrophysics and physical-chemistry.