Fragmentation of the PAH cations of Isoviolanthrene and Dicoronylene: A case made for interstellar cyclo[n]carbons as products of universal fragmentation processes

• Published in: International journal of mass spectrometry Vol. 485; p. 116996
• Main Authors: Hrodmarsson, Helgi Rafn, Bouwman, Jordy, Tielens, Alexander G.G.M., Linnartz, Harold
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2023
• ISSN: 1387-3806; 1873-2798
• DOI: 10.1016/j.ijms.2022.116996

The photo-induced fragmentation pathways of the cationic forms of isoviolanthrene (C34H18) and dicoronylene (C48H20) are systematically studied with mass spectrometry employing an ion trap coupled with a laser system. The mass spectra of these structurally different species display similar fragmentation products, akin to previous work on three dibenzopyrene isomers, but also display some differences. The products formed in the largest yields are pure carbon clusters, which are likely in the form of ionized cyclo[n]carbons (n = 11–15). These findings are relevant to get a full picture of the molecular makeup of interstellar space, particularly in heavily irradiated regions where polycyclic aromatic hydrocarbon (PAH) molecules are omnipresent and subject to harsh irradiation and are broken down into smaller components. These interstellar species are expected to include the PAH derivatives observed here, but which are not identified in space yet. [Display omitted] •Laser-induced fragmentation of two PAHs to investigate the influence of PAH size on fragmentation pathways.•Similarities found in the fragmentation pathways of the two PAH cations as well as in comparison with previous work.•Results imply the importance of cyclo[n]carbons as potential carbon sinks from photo-induced destruction of PAHs in space.