CAREER: Tiny Drops of Acid: Microwave Spectroscopy and Isomer-resolved IR Spectroscopy of Hydrohalic Acid-Water Clusters

职业：微小的酸滴：氢卤酸-水簇的微波光谱和异构体分辨红外光谱

• 批准号: 2340303
• 负责人: George Park
• 金额: $ 57万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-01 至 2029-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2340303&HistoricalAwards=false
• 关键词: CAREER; Tiny; Drops; Acid; Microwave

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, G. Barratt Park of Texas Tech University is developing broadband microwave spectroscopy-based tools for the automated assignment and structure determination of clusters in complex mixtures. The microwave structures will be combined with isomer-resolved IR measurements to obtain detailed information about small hydrohalic acid-water clusters. Microwave spectroscopy is a powerful method for determining the precise three-dimensional structure of a molecule or cluster of molecules, but spectra obtained from mixtures of unknown molecular species are extremely challenging to interpret because of their sheer complexity. Dr. Park and his students will use automated microwave and infrared spectroscopy techniques to unravel the complicated patterns and learn about the structure and vibrational dynamics of the world’s tiniest drops of acid, consisting of a single acid molecule dissolved by a handful of water molecules. Their studies could provide crucial benchmarks for the theoretical description of aqueous clusters and could lead to significant advances in chemical structure determination from microwave spectra of mixtures. The Park group will develop a microwave spectrometer to provide hands-on instruction for undergraduate students and will perform community outreach with future-scientist middle school girls. Technological advances in frequency-flexible broadband microwave spectroscopy enable entirely new approaches to microwave structure determination in complex mixtures. The current capabilities of automated assignment algorithms will be extended to more complex, non-rigid Hamiltonians. The primary target of this investigation will be hydrohalic acid-water clusters with a single HX molecule and 3-10 water molecules. To date, existing spectroscopic approaches have only enabled microwave structures and unambiguous, undisputed IR assignment of very small clusters with fewer than three water molecules. A key goal of this investigation will be to obtain high-resolution measurements of the structure and vibrational dynamics of the smallest clusters that lead to dissociation. The isotopic substitution of the clusters will be varied in a controlled way, facilitating the assignment of a complete set of substitution structures, which will allow the determination of the microwave structure. Isomer-resolved IR spectra of neutral clusters will be obtained by IR-microwave double resonance. Advances in methodology that will be enabled by the proposed work could make progress towards the elusive goal of allowing chemical structures to be determined from microwave spectra of mixtures in an efficient way by a non-expert.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构、动力学和机理 A (CSDM-A) 项目的支持下，德克萨斯理工大学的 G. Barratt Park 正在开发基于宽带微波光谱的工具，用于自动分配和确定簇的结构。微波结构将与异构体分辨红外测量相结合，以获得有关小型氢卤酸-水簇的详细信息。微波光谱是确定精确三维结构的强大方法。分子或分子簇，但从未知分子种类的混合物中获得的光谱由于其极其复杂性而极难解释。 Park 博士和他的学生将使用自动微波和红外光谱技术来揭示复杂的模式并了解其结构。他们的研究可以为水簇的理论描述提供重要的基准，并可能导致化学结构测定的重大进展。帕克小组将开发一种微波光谱仪，为本科生提供实践指导，并将与未来科学家的中学生进行社区推广。频率灵活的宽带微波光谱技术的进步使微波的全新方法成为可能。自动分配算法的当前功能将扩展到更复杂的非刚性哈密顿量，该研究的主要目标是具有单个 HX 分子和 3-10 的氢卤酸-水簇。迄今为止，现有的光谱方法只能对少于三个水分子的非常小的团簇进行微波结构和明确、无可争议的红外分配，这项研究的一个关键目标是获得结构和振动的高分辨率测量。导致解离的最小团簇的动力学将以受控的方式变化，从而促进一整套取代结构的分配，这将允许确定微波结构。中性团簇的异构体分辨红外光谱将通过红外-微波双共振获得，所提出的工作将实现的方法学进步可能会在实现从混合物的微波光谱中确定化学结构这一难以实现的目标方面取得进展。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。