Probing The Origins Of Chemical Complexity

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The origins of the complex chemical soup from which life arose on our planet remain to some extent clouded. However, it has become increasingly clear that at least some of that chemical complexity originated from the dense molecular cloud from which our solar system condensed nearly 5 billion years ago. Complex organic molecules are known to be formed in the icy mantles of interstellar dust grains in the cold depths of such dense molecular clouds and may have seeded our primordial atmosphere and oceans. In these cold, dark regions, the only realistic energy source for promotion of chemical change is high energy (>keV) particle and photon radiation. Such radiation generates within the icy grain mantles a shower of low energy secondary electrons that are the true agents of chemical change. This programme seeks to appy both qualitative and quantitative surface science techniques and methodolgies to investigate the formation of complex organics from extremely simple precursor ice mixtures, e.g. H2O/CO, H2O/NH3/CO etc. under controlled low energy electron irradiation. Reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD) and micrgravimetric methods will be combined to investigate the evolution of the surface chemical state while gas phase products will be detected by quadrupole mass spectrometry (QMS) as a function of both electron energy and beam current.