High-Field Solid-State Dynamic Nuclear Polarization with Paramagnetic Systems Beyond Simple Spin 1/2

超越简单自旋的顺磁系统高场固态动态核极化 1/2

• 批准号: 2411584
• 负责人: Song-I Han
• 金额: $ 58.05万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2411584&HistoricalAwards=false
• 关键词: Field; Solid; State; Dynamic; Nuclear

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Song-I Han at the Northwestern University is working to improve our understanding of solid-state Dynamic Nuclear Polarization (DNP), an important means of boosting the sensitivity of Nuclear Magnetic Resonance (NMR), thereby expanding its reach to a wider scope of chemical systems. NMR is a widely used tool for characterizing the composition and dynamics of chemical systems. It is, for example, the technical basis of Magnetic Resonance Imaging (MRI), an important medical diagnostic tool. Dr. Han and her group are devising new probes and new experimental protocols to substantially improve the resolution and sensitivity of NMR analysis of samples containing species and of properties currently not amenable to NMR analysis. The research offers interdisciplinary training opportunities to graduate students by providing hands-on experience in technology and hardware development. The educational impact is enhanced through a structured undergraduate research program, Hands-On-Spin (hSPIN), engaging undergraduate students in instrument development. Dr. Han's research focusses on development of innovative methods for spin manipulations and novel instrumental capabilities, targeting improved understanding and a wider scope of applicability for high-field solid-state Dynamic Nuclear Polarization (DNP). Specifically, her group is using a novel sensitizer scheme to reveal DNP from high-spin systems that would otherwise be invisible to DNP. In the course of these studies, they are clarifying the mechanism behind the Overhauser effect (OE) in insulating solids, unraveling the competition between electron spin exchange (J) and dipolar couplings (D) in DNP under Magic Angle Spinning (MAS), and improving understanding of the potential and range of hyperfine DNP spectroscopy to measure transition metal – nuclear spin distances. The studies are uncovering new DNP mechanisms and novel experimental approaches to extend DNP to spin systems beyond S=1/2. These aims are enabled by developing innovative instrumental capabilities for concurrent electron (e) and nuclear (n) spin resonance excitation and detection; arbitrary waveform generated (AWG) pulse shaping to achieve coherent and/or spin dynamics-assisted e-n polarization transfer; and two-frequency pump-probe 2D Electron DOuble Resonance (ELDOR), under static and MAS conditions.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.

在化学测量和化学成像计划的支持下，西北大学的Song-I Han教授正在努力提高我们对固态动态核极化（DNP）的理解，这是提高核磁共振（NMR）敏感性的重要手段，从而扩展了其范围为化学系统的范围扩展。 NMR是一种用于表征化学系统组成和动力学的广泛使用的工具。例如，它是磁共振成像（MRI）的技术基础，这是一个重要的医学诊断工具。 Han博士和她的小组正在设计新的问题和新的实验方案，以实质上提高了NMR分析的分析和敏感性，这些NMR分析包含物种和当前不适合NMR分析的属性。该研究通过提供技术和硬件开发方面的动手经验为研究生提供跨学科的培训机会。通过一项结构化的本科研究计划（HSPIN），从事仪器开发，从而增强了教育影响。 Han博士的研究重点是开发用于旋转操作和新型仪器能力的创新方法，以提高理解以及对高场固态动态核极化（DNP）的更广泛范围。具体来说，她的小组正在使用一种新型的传感器方案来揭示高自旋系统的DNP，否则这些系统对DNP看不见。在这些研究的过程中，它们在隔离固体方面的过度大关效应（OE）背后的机制在魔术角度旋转（MAS）下揭示了DNP中电子旋转交换（J）和偶性耦合（D）之间的竞争，并提高了对超精美DNP光谱金属的潜在和范围的核旋转金属的潜在和范围。这些研究正在发现新的DNP机制和新型实验方法，以将DNP扩展到s = 1/2的旋转系统。这些目标是通过为并发电子（E）和核（n）旋转共振兴奋和检测开发创新的仪器能力来实现这些目标的；产生的任意波形（AWG）脉冲成型以实现相干和/或自旋动力学辅助的E-N极化转移；在静态和MAS条件下，两种频率的泵浦探针2D电子双重共振（ELDOR）。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响评估审查标准，通过评估被认为是珍贵的支持。