IR-PD spectroscopy of the astrochemically relevant HCCS+ and [C 2 H 2 S]+ ions Vincent Richardson 1 , J. A. Diprose 1 , K. Steenbakkers 2 , M. Michielan 3 , M. Polášek 4 , S. Brünken 2 , D. Ascenzi 3 , C. Romanzin 5,6 1 Department of Physics, University of Liverpool, UK, 2 Institute for Molecules and Materials, FELIX Laboratory, Radboud University, The Netherlands, 3 Department of Physics, University of Trento, Italy, 4 J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Czechia, 5 Université Paris-Saclay, CNRS, France, 6 Synchrotron Soleil, L’Orme des Merisiers, France HCCS + was recently detected towards the cold dark cloud TMC-1 [1], the first detection of a protonated radical in such an environment, where its formation was assigned to the protonation of CCS. As CCS has been observed in astrochemical environments ranging from Sgr B2 [2], IRC+10216 [3], the protoplanetary disk surrounding GG Tau [4], at least 14 cirrus and Clemens Barvainis cores [5], and the Horsehead nebula, a Photon-Dominated Region (PDR) [6], there is a high likelihood that HCCS + is also present in these regions. Similarly, while no [C 2 H 2 S] + isomers have yet been observed, they could feasibly be formed by the protonation of the recently-observed HCCS neutral [7]. We present IR-PD spectra of both the HCCS + ion (formed by dissociative ionization of 2,5 dibromothiophene) and [C 2 H 2 S] + (formed by dissociative ionization of thiophene). The spectra have been measured via the irradiation of H 2 -tagged complexes in a cryogenic 22-pole trap within the FELion instrument [8] at the FELIX light source, with identification of the [C 2 H 2 S] + isomers present made through comparison with computed spectra. These results allow for future observations of these ions, while the characterization of these dissociative ionization processes can be applied for use as part of reactivity studies of these ions. References
1. C. Cabezas et al., A&A, 657, L4 (2022) 2. S. Saito et al., ApJ, 317, L115 (1987) 3. J. Cernicharo et al., A&A, 181, L9 (1987) 4. N. T. Phuong et al., A&A, 653, L5 (2021) 5. B. E. Turner, H. -H. Lee and E. Herbst, ApJ Supp. Series, 115, 91 (1988) 6. P. Rivière-Marichalar et al., A&A, 628, A16 (2019) 7. J. Cernicharo et al. A&A, 648, L3 (2021) 8. P. Jusko et al. Faraday Discuss. 217, 172 (2019)
P41
© The Author(s), 2023
Made with FlippingBook Learn more on our blog