University of Illinois Urbana-Champaign

Detection of non-emission vibronic bands of thiophenoxy radical by absorption spectroscopy

Araki, Mitsunori

Content Files
1417721.pptx
3863.pdf

Permalink

https://hdl.handle.net/2142/104314

Description

Title
Detection of non-emission vibronic bands of thiophenoxy radical by absorption spectroscopy
Author(s)
Araki, Mitsunori
Contributor(s)
  • Tsukiyama, Koichi
  • Oyama, Takahiro
  • Negishi, Mayu
  • Sato, Haruka
Issue Date
2019-06-21
Keyword(s)
Astronomy
Date of Ingest
  • 2019-07-15T22:16:39Z
  • 2020-01-25T19:31:24Z
Abstract
Diffuse Interstellar Bands (DIBs) are absorption bands detected in diffuse clouds by optical observations. Although $\sim$ 600 DIBs have been found so far, only the five bands were assigned to the fullerene cation and the other bands are not identified yet. Recently, benzonitrile (\chem{C_6H_5CN}) was detected in interstellar space by radio as the first aromatic compound [1]. Thus, thiophenoxy radical (\chem{C_6H_5S}) is received much attentions as a candidate of DIBs, because sulfur is a dominant element of interstellar molecules. Fluorescence excitation spectra of the $^{2}A_{2}$--X $^{2}B_{1}$ electronic transition of \chem{C_6H_5S} showed the origin band as the strongest peak [2]. However, in our previous work, absorption spectra of phenoxy radical (\chem{C_6H_5O}) brought out the stronger vibronic bands than the origin band [3]. The fact suggests that intensities of higher vibronic bands of \chem{C_6H_5S} are lost by radiationless transitions in the fluorescence excitation spectra. Thus, stronger vibronic bands of \chem{C_6H_5S} are expected because of similarity of the two molecules. We investigated the vibronic bands in the 473--519 nm region by Cavity Ring Down spectroscopy and detected them. The strongest vibronic band at 4850 \AA was assigned to the 6a$_{0}^{2}$ + 6b$_{0}^{1}$ transition. This band may appear as DIB if sufficient amount of this radical exists in interstellar medium. [1] McGuire et al., Science, 359, 202 (2018). [2] Shibuya et al., J. Chem. Phys. 121, 237 (1988). [3] Araki et al., Astronomical J. 150, 113 (2015).
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/104314
DOI
https://doi.org/10.15278/isms.2019.FA01
Copyright and License Information
Copyright 2019 Mitsunori Araki

Owning Collections

Abstracts & Presentations - 2019 International Symposium on Molecular Spectroscopy PRIMARY