Molecular Synthesis in Astrophysical Ices

天体物理冰中的分子合成

基本信息

批准号：
1810630
负责人：
金额：
--
依托单位：
The Open University
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1810630
关键词：
Molecular Synthesis Astrophysical Ices

项目摘要

The continuous cycle of star formation, evolution and death is driven by a complex interplay between interstellar gas, dust and radiation [1]. The interstellar medium (ISM) is a rich chemical factory, with over 170 molecular species identified to date [2], mostly observed in star-forming regions. Star formation begins in dense molecular clouds, where cold (~10 K) interstellar dust provides the surfaces for atoms and molecules to "freeze-out", forming icy mantles. These icy mantles are the largest molecular reservoirs in the ISM, where chemical reactions, driven by both non-thermal and thermal processes, produce more complex molecules that are subsequently released into the gas phase [3]. At the OU Astrochemistry laboratories, we investigate the physical and chemical properties of astrochemical ices in a controlled laboratory environment using ultra-high vacuum chambers and cryogenically cooled substrates to grow interstellar ice analogues [4-6]. The ices are characterised in situ, using Fourier-Transform Infrared Spectroscopy (FTIR) on-site or Vacuum Ultraviolet spectroscopy via access to synchrotron facilities (ASTRID2 in Aarhus, Denmark; and, in partnership with Dr Bhala Sivaraman at PRL in India, the Taiwan Synchrotron facility). The FTIR and VUV spectra are highly sensitive to the ice morphology and the interaction between the molecular species in the ice, and are also used to monitor any changes as a result of thermal (controlled heating) or non-thermal (UV, electron or ion irradiation) processing. Additionally, mass spectroscopy is used to monitor the species that are released into the gas phase (desorption and sputtering) during processing. Recent advances include the development of more realistic dust grain mimics using nanofabrication techniques to fashion carbonaceous and silicate microstructures to act as a grain template for ice deposition. We are also exploring use of ultrasonic levitation of dust grains as a method for studying astrochemistry on isolated grains.

恒星形成，进化和死亡的连续循环是由星际气体，尘埃和辐射之间的复杂相互作用驱动的[1]。星际培养基（ISM）是一家丰富的化学工厂，迄今为止鉴定出170多种分子物种[2]，主要在恒星形成区域中观察到。恒星形成始于密集的分子云，其中冷（约10 k）星际尘埃提供了原子和分子的表面，以“冻结”形成冰冷的地幔。这些冰冷的地幔是ISM中最大的分子储层，在该储层中，由非热和热过程驱动的化学反应产生了更复杂的分子，随后释放到气相中[3]。在OU天体化学实验室，我们使用超高的真空室和低温冷却的底物在受控的实验室环境中研究星体化学冰的物理和化学性质，以生长星际冰类似物[4-6]。这些冰是使用傅立叶转换红外光谱（FTIR）现场或真空紫外线光谱的特征。 FTIR和VUV光谱对冰形态和冰中的分子物种之间的相互作用高度敏感，并且还用于监测由于热（控制加热）或非热（紫外线，电子或离子辐照）处理而导致的任何变化。另外，质谱法用于监测加工过程中被释放到气相（解吸和溅射）的物种。最近的进步包括使用纳米制造技术开发更现实的灰尘晶粒模拟物，以时尚碳质和硅酸盐微观结构作为冰分沉积的谷物模板。我们还正在探索使用超声悬浮粉尘晶粒作为研究隔离晶粒的天体化学的一种方法。