The surface chemistry of complex organic molecules in space

该项目将利用实验和理论表面科学研究相结合的方法，调查在与星际空间以及彗星和行星冰有关的条件下复杂有机分子的吸附、处理（热处理以及电子和光子处理）和形成。这项研究是特别及时的，因为即将发射的詹姆斯韦伯太空望远镜（JWST），这将允许检测分子在太空中比以前更高的灵敏度。因此，这个学生将有机会参与与观测天文学直接相关的实验室和理论工作。COMs目前是天体化学中的一个热门话题，在一系列不同的环境中一直都有新的物种被发现。它们的重要性源于这样一个事实，即许多COM是前生物，即它们作为生物相关物种，如简单的氨基酸形成的前体。这项工作将使用实验和理论相结合，看看COM化学（包括形成，破坏和处理）模型尘埃颗粒表面。理论计算将指导实验工作，指出最可能的分子形成路线和破坏机制。实验工作将集中在处理COM，热和紫外线辐射和低能电子。这些实验将导致COM的破坏和/或解吸，并形成新的物种。其他实验也将着眼于含有较小分子的混合冰的紫外线和电子辐照，这些分子被认为是模型颗粒表面（石墨）上的COM（例如甲醇，CO，水，氨）的构建块。辐射的混合冰是重要的潜在形成途径COM。小分子（如甲醇）的紫外线或电子辐照先前已被证明会导致产生反应性片段，这些片段可以继续形成更大的物质。表面科学技术，包括表面红外光谱和程序升温脱附，将用于监测所研究的COM的形成和破坏

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