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.

从星际云到遥远卫星大气层的天文来源的分子组成非常令人感兴趣，因为它提供了对我们宇宙演化的洞察。例如，在恒星之间的云层中已知的超过180个分子，包括醇、醛和酮等有机化合物；其中一些被认为是益生菌的组成部分。这些星际云最终形成了新的太阳系，它们的化学成分是用望远镜追踪的，以探测单个分子吸收或发射光线时的不同分子指纹。这些独特的特征通常涉及分子旋转的变化，并在微波(MW)至远红外(FIR)波长发生。每年在偏远来源检测几种新化合物是用来完善它们的化学演化模型，但明确识别新物种需要基于实验室的光谱进行比较。 我的研究项目解决了这一需求，利用微波和红外光谱的最新进展，非常详细地测量了作为天体化学过程潜在成分的新型瞬时分子的最低能量状态。其中许多也是短暂的物种，推动着地球上的反应，包括那些涉及燃烧、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，还需要这些光谱来获得基本的分子性质，如几何结构、内部重排的障碍以及旋转和振动运动之间相互作用的性质。这种准确的分子水平信息加深了我们对瞬变化合物化学的理解，并将导致更好的模型和对所有类型的化学过程的控制。 这项研究的关键内容包括正在开发的新方法，用于在微波和冷杉区域产生和探测暂态物种的混合物。学员将使用马尼托巴大学两台最先进的定制傅里叶变换微波(FTMW)光谱仪来优化新化合物的生成。一种提供快速微波光谱测量，以识别气体混合物各组分的旋转跃迁，而另一种使用谐振腔，非常精确和灵敏地记录特定特征(一个接一个)。从光谱中提取的信息指导我们使用萨斯卡通的加拿大光源(CLS)同步加速器的FIR光束线来研究分子的振动指纹；这是世界上仅有的四个设备之一。我们开发了大数据的自动分配策略，以在未来几年处理复杂的MW和FIR光谱，这将为新的研究人员打开高分辨率光谱领域，并提出越来越具挑战性的科学问题。