BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

Propargyl alcohol (CHCCH₂OH) is a known stable isomer of the propenal (CH₂CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm^–1. Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C₆H₆) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C₃H₃) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C₆H₆ in the interstellar icy mantles