Summary:

Polycyclic aromatic hydrocarbons (PAHs) are abundant in the interstellar medium and act as catalytic surfaces in a crucial interplay between hot atomic gas and ultraviolet (UV) radiation. Especially in the dissociation fronts of giant, star forming gas clouds, PAHs will undergo competing reactions from the interaction with hydrogen (H) atoms and UV radiation leading to hydrogenation, dehydrogenation or carbon fragmentation.  This work reveals energetically favorable H₂ formation pathways through vibrational excitation of partially superhydrogenated PAHs; and reveals the importance of edge termination which greatly influences the stability of these possible H₂ factories in space.

Article:

https://iopscience.iop.org/article/10.3847/1538-4357/ad5bd8