A collaboration between the groups of Bjørk Hammer and Liv Hornekær in the Center for Interstellar Catalysis (InterCat) at IFA and Jos Oomens in FELIX Laboratory, Radboud University, the Netherlands, shows how ethylene is formed from fragmentation of superhydrogenated polycyclic aromatic hydrocarbons.

Fragmentation of polycyclic aromatic hydrocarbons (PAHs) is a possible formation route of small hydrocarbons in space. Understanding the molecular mechanisms of PAH fragmentation requires both experimental and theoretical efforts. Back in 2018, experimental PhD students (Frederik Doktor S. Simonsen, Rijutha Jaganathan, and Julianna Palotás) and a theoretical PhD student (Zeyuan Tang) started a collaboration on this topic under the supervision of Jos Oomens, Liv Hornekær, and Bjørk Hammer. This collaborative team have combined action spectroscopy techniques and quantum chemical calculations to investigate fragmentation of superhydrogenated PAHs. The fragmentation pathway is found to be sensitive hydrogenated edges (e.g. the degree of hydrogenation and the hydrogenated positions). Ethylene formation is more favorable from superhydrogenated PAHs with trio groups (three consecutive CH2 molecular entities) than from those with duo groups (two consecutive CH2 molecular entities).

This work is now accepted by Astronomy and Astrophysics. More information can be found in

https://arxiv.org/abs/2205.07705

https://doi.org/10.1051/0004-6361/202243202