The surface chemistry of complex organic molecules in space

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This project will use a combination of experimental and theoretical surface science studies to investigate the adsorption, processing (thermally and by electrons and photons) and formation of complex organic molecules (COMs) in conditions relevant to interstellar space and to cometary and planetary ices. This research is particularly timely because of the upcoming launch of the James Webb Space Telescope (JWST), which will allow the detection of molecules in space with much higher sensitivity than previously possible. This student will hence have the chance to be involved in laboratory and theoretical work directly relevant to observational astronomy. COMs are currently a hot topic in Astrochemistry, with new species being found all of the time in a range of different environments. Their importance stems from the fact that many COMs are pre-biotic i.e. they act as precursors to the formation of biologically relevant species such as simple amino acids.This work will use a combination of experiment and theory to look at COM chemistry (including formation, destruction and processing) on model dust grain surfaces. Theoretical calculations will guide the experimental work, by indicating the most likely molecular formation routes and destruction mechanisms. Experimental work will focus on processing of COMs, thermally and with UV radiation and low energy electrons. These experiments will lead to destruction and/or desorption of the COMs and also to the formation of new species. Additional experiments will also look at UV and electron irradiation of mixed ices containing smaller molecules, considered to be the building blocks of COMs (eg methanol, CO, water, ammonia) on a model grain surface (graphite). Irradiation of mixed ices is important as potential formation routes to COMs. UV or electron irradiation of small molecules (e.g. methanol) has previously been shown to lead to the production of reactive fragments which can go on to form larger species. Surface science techniques, including surface infrared spectroscopy and temperature programmed desorption, will be used to monitor the formation and destruction of the COMs investigated