Chemical Applications of Floquet State Spectroscopy

在化学系化学测量和成像(CMI)计划的支持下，威斯康星大学的约翰·赖特教授和他的研究小组正在开发一种名为Floquit态光谱的新技术。Floquit态光谱是核磁共振光谱的完全相干光学模拟。核磁共振光谱学利用无线电波与原子和分子相互作用，因其能够表征复杂的样品而在科学和技术中得到广泛应用。Floquit态光谱学承诺使用光而不是无线电波与分子相互作用的类似能力。该项目的目标是将Floquit态光谱应用于一系列在化学实际应用中非常重要的化学体系。例如，赖特教授和他的团队使用这项技术来确定分子中的原子必须如何弯曲、扭曲和拉伸，以改变将分子连接在一起的键。这些信息构成了合成化学的核心，因为它确定了反应的机理。该团队还与来自学术、工业和政府实验室的合作者合作，展示了弗洛奎特状态光谱在表征复杂材料方面的独特能力，并展示了该技术如何应用于许多科学和技术领域。该项目的更广泛影响包括这项新技术的广泛传播，学生培训机会，以及与斯佩尔曼学院的合作，该学院邀请少数族裔学生参与关于Floquit态光谱的夏季研究项目。Floquit态光谱测量基于同时驱动的多个振动和电子分子态的系统的响应。由此产生的量子力学纠缠叠加态根据Floquit态的波矢组合发出光。扫描分子共振的驱动频率会导致输出光束的倍增增强，从而提供了一种测量多维光谱的方法。本研究项目的一个主要重点是利用Floquit态光谱来探索化学反应的机理。创建一个Floquit态，它包含与由混沌热运动驱动的振动和电子态相同的振动和电子态，从而允许直接观察和控制反应。钴胺和Ru-Ru金属-金属络合物是该团队用来测试Floquit态光谱探索反应机理的能力的两种模型化合物。在钴胺中，挑战是理解导致C-Co键与底物结合时断裂率发生12个数量级变化的因素。在Ru络合物中，挑战是理解C-H键的胺化机制。该技术的推广包括与合作者合作将Floquit态光谱应用于复杂聚合物材料的表征、在玻璃中处理榄系元素核废料、对光化学反应的飞秒受激拉曼研究，以及开发胰腺癌的医学诊断。其他更广泛的影响包括对研究生的高级培训，以及通过与斯佩尔曼学院的合作努力扩大参与。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Professor John Wright and his research group at the University of Wisconsin are developing a new technique called Floquet state spectroscopy. Floquet state spectroscopy is the fully coherent optical analogue of nuclear magnetic resonance (NMR) spectroscopy. NMR spectroscopy, which uses radio waves to interact with atoms and molecules, is used extensively in science and technology because of its ability to characterize complex samples. Floquet state spectroscopy promises similar capabilities using light, rather than radio waves, to interact with molecules. The goal of this project is to apply Floquet state spectroscopy to a range of chemical systems that are important in practical applications of chemistry. For example, Professor Wright and his team use the technique to determine how the atoms within a molecule must bend, twist, and stretch in order to change the bonds that hold the molecule together. This information forms the heart of synthetic chemistry because it identifies the mechanisms responsible for a reaction. The team also works with collaborators from academic, industrial, and government laboratories to demonstrate the unique capabilities of Floquet state spectroscopy for characterizing complex materials and to show how the technique can be applied in many fields of science and technology. The broader impacts of the project include wide dissemination of this new technology, student training opportunities, and a collaboration with Spelman College that engages minority students in summer research projects on Floquet state spectroscopy.Floquet state spectroscopy measures the response of a system based on simultaneously driven multiple vibrational and electronic molecular states. The resulting quantum mechanically entangled superposition state emits light according to the wavevector combinations of the Floquet states. Scanning the driving frequencies across resonances of a molecule results in multiplicative enhancements of the output light beams and thus provides a way to measure multidimensional spectra. A primary focus of this research project is using Floquet state spectroscopy to probe the mechanisms of chemical reactions. Creating a Floquet state that contains the same vibrational and electronic states as those driven by chaotic thermal motions allows direct observation and control of a reaction. Cobalamin and a Ru-Ru metal-metal complex are two model compounds that the team is using to test the ability of Floquet state spectroscopy to probe reaction mechanisms. In cobalamin, the challenge is to understand the factors responsible for the 12-orders of magnitude change in the scission rate of the C-Co bond upon binding with a substrate. In the ruthenium complex, the challenge is understanding the mechanism for the amination of C-H bonds. Dissemination of the technology includes working with collaborators to apply Floquet state spectroscopy for complex polymeric materials characterization, disposal of actinide nuclear waste in glasses, femtosecond stimulated Raman studies of photochemical reactions, and development of medical diagnostics for pancreatic cancer. Additional broader impacts include advanced training for graduate students as well as the efforts to broaden participation through the collaboration with Spelman College.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.