Surface Science Studies of the Non-Thermal Processing of Model Astrophysical Ices

该项目将利用实验表面科学研究，在与星际空间以及彗星和行星冰有关的条件下，调查模型天体物理冰的非热处理(通过电子和光子)。这项研究特别及时，因为詹姆斯·韦伯太空望远镜(JWST)即将发射，它将允许以比以前可能的更高的灵敏度探测太空中的分子。学生将使用低能电子或紫外线照射冰块，然后使用表面科学技术，如程序升温解吸和表面红外光谱来监测辐射产物。学生还将使用新开发的新型反射吸收紫外可见光谱仪，在与各种天体物理环境相关的条件下，现场测量模型天体物理冰的折射率。这些过程将在不同的模型尘埃颗粒表面上进行研究，包括碳质和硅质尘埃颗粒类似物，以进一步研究颗粒表面在观察到的化学中的作用。在这项计划期间进行的工作的具体目标是：-进行模型天体物理冰的紫外线辐射和低能电子非热处理的实验研究。-利用反射吸收紫外-可见光谱对模型天体物理冰的折射率进行实验研究-利用实验数据建立描述天体物理条件下非热解吸的模型。

This project will use experimental surface science studies to investigate the non-thermal processing (by electrons and photons) of model astrophysical ices 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. The student will use low energy electrons or ultra-violet light to irradiate ices and will then use surface science techniques such as temperature programmed desorption and surface infrared spectroscopy to monitor the products of the irradiation. The student will also use a newly developed, novel, reflection-absorption UV-visible spectrometer to measure the refractive index for model astrophysical ices in situ under conditions relevant to various astrophysical environments. These processes will be investigated on various model dust grain surfaces including carbonaceous and silicaceous dust grain analogues to further investigate the role of the grain surface in the observed Chemistry.The specific objectives of the work to be undertaken during this project are:- To undertake experimental investigations of the non-thermal processing of model astrophysical ices by ultra-violet radiation and low energy electrons.- To undertake experimental studies of the refractive index of model astrophysical ices using reflection-absorption UV-visible spectroscopy- To use data from the experiments to develop models that describe non-thermal desorption under astrophysical conditions