Infrared Spectra of Acetylene Diluted in Solid Nitrogen upon Irradiation with Vacuum Ultraviolet Light and Electrons

Abstract

Infrared spectra and chemical reactions of acetylene diluted in solid nitrogen at 10 K upon irradiation with vacuum ultraviolet (VUV) light and energetic electrons were investigated in separate experiments. Irradiation of the matrix sample with VUV light peaking at 160 and 121.6 nm yielded simple products, including C₂H, CN, and isomers of C₂N₂. In contrast, electron irradiation of a similar sample generated N₃, C₂H, and various nitriles. The reaction mechanisms for photolysis and radiolysis of the matrix samples are discussed. Our results may help explain the distribution of trace species detected in the atmosphere of Titan. In addition, the UV absorption spectrum of the electron-bombarded icy sample was obtained and might be useful for future spectral investigations of Pluto by New Horizons.