Radiation-induced closure of the second aromatic ring: Possible way to PAH starting from a styrene-acetylene complex

Abstract The radiation-induced assembling of the naphthalene molecule was first directly observed under X-ray irradiation of the isolated styrene-acetylene complex in a solid krypton matrix at 6 K using FTIR spectroscopy. The observation of naphthalene radical cation in the presence of electron scavenger suggests a cationic pathway of this reaction. This finding makes it possible to propose a new mechanism for the formation of polycyclic aromatic hydrocarbons in astrochemical ices.