Wendy Brown, University of Sussex, Dept.of Chemistry

Thermal and UV processing of complex organic molecules in space

Recent astronomical observations have shown that complex organic molecules (COMs) are found in a broad range of astrophysical environments, including interstellar space and cometary ices. Models show that chemistry in ices, particularly that induced by ultra-violet irradiation, plays an important role in the formation of many COMs. Thermal processing is also extremely important in releasing the COMs into the gas phase where they can go on to partake in further chemistry. We have therefore used surface science techniques, including surface infrared spectroscopy and temperature programmed desorption, to investigate the adsorption, thermal and ultra-violet processing of a range of C, H and O containing COMs which have been detected in various environments. We have observed UV induced desorption and dissociation for methyl formate, glycolaldehyde and acetaldehyde. We have also elucidated the trapping and desorption behaviour of a number of COMs,which has allowed us to develop a general model that describes the behaviour of C, H and O containing COMs in the presence of water ice.