New Tools and New Approaches for Spectroscopy, Kinetics and Dynamics in Uniform Supersonic Flows

均匀超音速流中光谱学、动力学和动力学的新工具和新方法

基本信息

批准号：
1665207
负责人：
Arthur Suits
金额：
$ 45万
依托单位：
University of Missouri-Columbia
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-15 至 2020-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1665207&HistoricalAwards=false
关键词：
New Tools Approaches Spectroscopy Kinetics

项目摘要

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Arthur Suits of the University of Missouri, Columbia, is developing new laser and microwave spectroscopy techniques to study the detailed interactions and properties a range of reactive molecules (for example, organic molecules that contain multiple bonds, like butadiene, allene and propyne) and molecular clusters (for example water). These new methods provide insight into the structures of these molecules, and how these molecules react to form different product molecules when they absorb energy. In addition to new insights about the structure and reactivity of the molecules considered in this project, the research is also continuing the development of laser and spectroscopy techniques from which other research groups can benefit. In particular, the Suits group is continuing to develop and improve a data analysis software package (Finite Slice Analysis, or "FinA"). The group makes the software available to other researchers free of charge. In addition to the training received in cutting-edge laser and spectroscopic techniques, the students involved in this project also gain experience in ab initio electronic structure calculations so they have a solid foundation and some practical experience with these methods. These studies take advantage of two new instruments being developed to probe the reaction dynamics, spectroscopy, and low temperature kinetics of polyatomic molecules. Particular attention is directed to radical species important in atmospheric chemistry and astrochemistry. The first of these instruments combines Chirped-pulse Fourier-transform microwave technique with intense low-temperature pulsed uniform supersonic flows, allowing broadband rotational spectroscopy to be used as a nearly universal tool in the study of photodissociation, product branching, spectroscopy and low temperature kinetics. The second instrument combines the same uniform supersonic flows with high-resolution ultra-sensitive continuous-wave cavity ring-down spectroscopy (CRDS), providing capabilities complementary to those of the microwave-based system. Both of these instruments are the first of their kind. These studies are applied 1) to probe detailed product branching in photodissociation reactions; 2) to develop microwave-infrared double resonance methods for application to vibrational spectroscopy of radicals and reaction intermediates; 3) to probe reaction kinetics at low temperature with new detail including vibrational dependence and isomer- and conformer-specificity, and for transient radical species in low abundance; 4) to characterize the thermochemistry of water clusters such as the water hexamer and other non-covalently bound systems; and 5) to adapt sensitive CRDS methods to detect and characterize important atmospheric and astrochemical radicals and reaction intermediates kinetically trapped in local energy minima at low temperature in the flow.

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Arthur Suits of the University of Missouri, Columbia, is developing new laser and microwave spectroscopy techniques to study the detailed interactions and properties a range of reactive molecules (for example, organic molecules that contain multiple bonds, like butadiene, allene and propyne) and molecular集群（例如水）。这些新方法可洞悉这些分子的结构，以及这些分子在吸收能量时如何反应形成不同的产物分子。除了对该项目中考虑的分子的结构和反应性的新见解外，该研究还继续开发激光和光谱技术，其他研究小组可以从中受益。特别是，Suits Group正在继续开发和改进数据分析软件包（有限切片分析或“ Fina”）。该小组将软件免费提供给其他研究人员。除了在尖端激光和光谱技术方面接受的培训外，参与该项目的学生还获得了从头算电子结构计算的经验，因此他们具有坚实的基础和这些方法的实践经验。这些研究利用了开发两种新仪器来探测多原子分子的反应动力学，光谱和低温动力学。特别关注的是对大气化学和星体化学重要的激进物种。这些仪器中的第一种结合了狭窄的脉冲傅立叶转换微波技术和强烈的低温脉冲均匀均匀的超音速流，从而使宽带旋转光谱法被用作光电传播，产品分支，光谱，光谱，光谱和低温动力学的几乎通用工具。第二个仪器将相同的均匀超音速流与高分辨率的超敏感连续波腔环形戒指光谱（CRDS）结合在一起，为基于微波炉的系统提供了互补的能力。这两种仪器都是同类工具。这些研究应用于1）在光解离反应中探测详细的产品分支； 2）开发用于将自由基和反应中间体的振动光谱应用应用于振动光谱的微波联邦双共振方法； 3）在低温下探测反应动力学，包括新的细节，包括振动依赖性和异构体和构象异构体特异性，以及低丰度的短暂自由基物种； 4）表征水簇的热化学，例如水己酯和其他非共价结合的系统； 5）要适应敏感的CRD方法，以检测和表征重要的大气和天体化学自由基和反应中间的中间体在流动中的低温下，在局部能量最小值中被困在局部能量中。