A Fourier-transform ion-cyclotron-resonance study of the reactions of polycyclic aromatic hydrocarbon cations with molecules of interstellar interest

The reactivity of naphthalene and pyrene radical cations and their derivatives (C₁₀H_n⁺, n=6,7,8,9), C₁₆H_n (n=9,10,11) has been studied with molecules of interstellar interest in an ion cyclotron resonance apparatus. The radical cations C₁₀H₈⁺ and C₁₆H₁₀⁺ are unreactive with H₂,CO,H₂O and NH₃. Adduct formation is the only channel for almost all reactions of C₁₀H₇⁺ with these molecules. The implications of these results for the stability of polycyclic aromatic hydrocarbon (PAH) cations in the interstellar medium are briefly discussed. Exploratory studies of the ion chemistry of a larger PAH, coronene, have also been done.