Biennier, L. ; Jayaram, V. ; Suas-David, N. ; Georges, R. ; Singh, M. Kiran ; Arunan, E. ; Kassi, S. ; Dartois, E. ; Reddy, K. P. J. (2016) Shock-wave processing of C60 in hydrogen Astronomy & Astrophysics, 599 . A42. ISSN 0004-6361
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Official URL: http://doi.org/10.1051/0004-6361/201629067
Related URL: http://dx.doi.org/10.1051/0004-6361/201629067
Abstract
Context. Interstellar carbonaceous particles and molecules are subject to intense shocks in astrophysical environments. Shocks induce a rapid raise in temperature and density which strongly affects the chemical and physical properties of both the gas and solid phases of the interstellar matter. Aims. The shock-induced thermal processing of C 60 particles in hydrogen has been investigated in the laboratory under controlled conditions up to 3900 K with the help of a material shock-tube. Methods. The solid residues generated by the exposure of a C 60 /H 2 mixture to a millisecond shock wave were collected and analyzed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman micro-spectroscopy, and infrared micro-spectroscopy. The gaseous products were analyzed by Gas Chromatography and Cavity Ring Down Spectroscopy. Results. Volatile end-products appear above reflected shock gas temperatures of ~2540 K and reveal the substantial presence of small molecules with one or two C atoms. These observations confirm the role played by the C 2 radical as a major product of C 60 fragmentation and less expectedly highlight the existence of a single C atom loss channel. Molecules with more than two carbon atoms are not observed in the post-shock gas. The analysis of the solid component shows that C 60 particles are rapidly converted into amorphous carbon with a number of aliphatic bridges. Conclusions. The absence of aromatic CH stretches on the IR spectra indicates that H atoms do not link directly to aromatic cycles. The fast thermal processing of C 60 in H 2 over the 800–3400 K temperature range leads to amorphous carbon. The analysis hints at a collapse of the cage with the formation of a few aliphatic connections. A low amount of hydrogen is incorporated into the carbon material. This work extends the range of applications of shock tubes to studies of astrophysical interest.
Item Type: | Article |
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Source: | Copyright of this article belongs to ResearchGate GmbH |
ID Code: | 131035 |
Deposited On: | 02 Dec 2022 08:18 |
Last Modified: | 02 Dec 2022 08:18 |
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