Microwave and synchrotron far infrared spectroscopy of transient molecules

瞬态分子的微波和同步加速器远红外光谱

• 批准号: RGPIN-2016-06053
• 负责人: vanWijngaarden, Jennifer
• 金额: $ 2.62万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710114
• 关键词: Microwave; synchrotron; far; infrared; spectroscopy

The molecular composition of astronomical sources, from interstellar clouds to the atmospheres of remote moons, is of great interest as it provides insights into the evolution of our Universe. For example, more than 180 molecules are known in clouds between stars including organic compounds such as alcohols, aldehydes and ketones; some of which are thought to be prebiotic building blocks. These interstellar clouds ultimately form new solar systems and their chemical composition is tracked using telescopes to detect distinct molecular fingerprints as individual molecules absorb or emit light. These unique features most often involve changes in molecular rotation and occur at microwave (MW) through far infrared (FIR) wavelengths. Detection of several new compounds in remote sources each year is used to refine models of their chemical evolution but the unambiguous identification of novel species requires laboratory-based spectra for comparison. My research program addresses this need using the latest advances in both MW and FIR spectroscopy to measure, in great detail, the lowest energy states of novel transient molecules that are potential components of astrochemical processes. Many of these are also short-lived species that drive reactions on Earth including those involved in combustion, thin film deposition and atmospheric reactions. In addition to characterizing unique fingerprints of new compounds, these spectra are needed to derive fundamental molecular properties such as the geometry, barriers to internal re-arrangements and the nature of interactions between rotational and vibrational motions. This accurate molecular-level information furthers our understanding of the chemistry of transient compounds and will lead to better models and control of chemical processes of all types. Key elements of this research include the ongoing development of new methods for producing and probing mixtures of transient species in the MW and FIR regions. Trainees will use two state-of-the-art custom-built Fourier transform microwave (FTMW) spectrometers at the University of Manitoba to optimize the generation of novel compounds. One provides fast MW spectral surveys to identify rotational transitions of individual components of a gaseous mixture while the other uses a resonator cavity to then record specific features (one by one) very precisely and sensitively. Information extracted from the spectra guides our investigation of vibrational fingerprints of molecules using the FIR beamline of the Canadian Light Source (CLS) synchrotron in Saskatoon; one of only four facilities in the world equipped for this purpose. Our development of big data' automated assignment strategies to deal with complex MW and FIR spectra over the next few years will open the field of high resolution spectroscopy to new researchers and increasingly challenging scientific questions.

从星际云到偏远卫星大气的天文来源的分子组成引起了人们的极大兴趣，因为它为我们宇宙的演变提供了见解。例如，恒星之间的云中已经知道了180多个分子，包括有机化合物，例如醇，醛和酮。其中一些被认为是益生元的基础。这些星际云最终形成了新的太阳系，并使用望远镜追踪其化学成分，以检测不同的分子指纹，因为单个分子吸收或发出光。这些独特的特征通常涉及分子旋转的变化，并通过远红外（FIR）波长在微波炉（MW）发生。每年远程来源中几种新化合物的检测用于完善其化学演化的模型，但是对新物种的明确鉴定需要基于实验室的光谱进行比较。 我的研究计划使用MW和FIR光谱的最新进展来解决这一需求，以详细介绍新型短暂分子的最低能量状态，这些瞬态分子是天体化学过程的潜在组成部分。其中许多也是短寿命的物种，这些物种在地球上驱动反应，包括参与燃烧，薄膜沉积和大气反应的反应。除了表征新化合物的独特指纹外，还需要这些光谱来得出基本的分子特性，例如几何形状，内部重新排列的障碍以及旋转和振动运动之间相互作用的性质。这种准确的分子级信息进一步发展了我们对瞬态化合物化学的理解，并将导致更好的模型和控制所有类型的化学过程。 这项研究的关键要素包括持续开发用于生产和探测MW和FIR区域瞬时物种混合物的新方法。学员将使用曼尼托巴大学的两个最先进的定制傅立叶变换微波炉（FTMW）光谱仪来优化新型化合物的产生。一种提供快速的MW光谱调查，以鉴定气态混合物的单个组件的旋转过渡，而另一个则使用谐振器腔，然后非常精确和敏感地记录特定特征（一个）。从光谱中提取的信息指导了我们使用加拿大光源（CLS）同步器的FIR光束线对分子振动指纹的研究；为此目的，世界上仅有的四个设施之一。在未来几年中，我们开发了大数据的自动化分配策略来处理复杂的MW和FIR光谱，将向新的研究人员和越来越具有挑战性的科学问题开放高分辨率光谱的领域。