Abstract

This talk will describe the application of surface science techniques to problems which are of relevance to astronomy. A detailed study of the adsorption and desorption of a range of astrophysically relevant molecules, including methanol, water, ammonia, ethanol and formic acid, has been performed on a highly oriented pyrolytic graphite (HOPG) surface. These molecules are all found in star forming regions of space in abundances that cannot be accounted for by gas phase reactions. Astronomers have hypothesised that these molecules are formed by heterogeneous reactions which take place on the surface of dust grains and it is this hypothesis that our experiments are designed to test. We have used a combination of temperature programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS) to investigate the way in which these molecules adsorb on, and desorb from, an HOPG surface.

The information obtained from these experiments is of direct relevance to astronomers, as the measured desorption energies can be incorporated directly into astronomical models. This in turn helps to lead to a greater understanding of star formation, and hence of the Universe in which we live.