Chemical reactions occurring in the interstellar medium and on planetary bodies in the outer Solar System (e.g., Titan) may be catalyzed by small ice covered graphitic and/or silicate grains to form larger species such as prebiotic molecules. However, non-thermal, radiation-induced, grain-mediated reactions relevant to astrochemistry throughout the Universe have not been well studied. Here, low temperature ice mixtures deposited on graphitic and silicate materials have been interrogated using a variety of analytic surface science methods after irradiation by low energy electrons (5-50 eV) and ultraviolet/vacuum ultraviolet photons (118-355 nm). Resonance enhanced multiphoton ionization (REMPI) and electron stimulated desorption (ESD) are paired with time-of-flight mass spectrometry (TOF-MS) to detect the state-resolved and scattered reaction products. Infrared spectroscopy is also used to identify products. The facile formation of molecules such as H2 and HCN has been observed, and preliminary results suggest that more complex species form under conditions where radical diffusion dominates.

Photon and electron induced reaction dynamics at the vacuum-surface and buried interface of ice covered graphitic and silicate grains

240th National Meeting (2010)

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