We compared the IR absorption spectra of C2H2/N2 (1/250) ice samples at 10 K irradiated with 2000 eV electrons and VUV photons during deposition. Electron bombardment of the icy samples produced N3 radicals and a variety of products containing �CN groups. However, photolysis of the ice samples yielded 15 times more C2H radicals than those produced by radiolysis; this amount of C2H may play a key role in the formation of larger carbon clusters in some planetary atmospheres. The present work, which compares different excitation effects, may improve our understanding of the atmospheric chemistry of Titan.Furthermore, far-UV absorption spectra of the electron-bombarded ice samples were obtained, and the main carriers associated with the absorption bands were assigned according to the observed products identified by IR spectroscopy. Our results suggest both N3 and C2 radicals exist on Pluto. Current signal to noise ratios of Hubble Space Telescope (HST) spectra in the UV region are limited by low flux of solar illumination. Therefore, identification of other trace species through UV or IR spectroscopy remains difficult. The New Horizons spacecraft is expected to reach Pluto and other TNOs in 2015; detecting and mapping these species of these remote worlds may be possible.

Irradiation of acetylene diluted in solid nitrogen with VUV light and energetic electrons

248th National Meeting (2014)

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