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.

在化学系化学测量与成像项目的支持下，西北大学韩松义教授正在努力提高我们对固态动态核极化（DNP）的理解，这是提高核敏感度的重要手段。磁共振 (NMR) 从而将其范围扩展到更广泛的化学系统。 NMR 是一种广泛使用的表征化学系统的组成和动力学的工具，例如，它是磁共振的技术基础。成像 (MRI) 是一种重要的医学诊断工具，Han 博士和她的团队正在设计新的探针和新的实验方案，以大幅提高对含有目前不适合 NMR 研究的物质和特性的样品进行 NMR 分析的分辨率和灵敏度。通过提供技术和硬件开发方面的实践经验，为研究生提供跨学科培训机会。通过结构化的本科生研究计划 Hands-On-Spin (hSPIN)，让本科生参与仪器开发，从而增强了教育影响。研究专注于开发自旋操纵的创新方法和新颖的仪器能力，旨在提高对高场固态动态核极化（DNP）的理解和更广泛的适用性，具体来说，她的团队正在使用一种新颖的敏化剂方案来揭示 DNP。在这些研究过程中，他们正在阐明绝缘固体中奥弗豪瑟效应 (OE) 背后的机制，揭示电子自旋之间的竞争。魔角旋转 (MAS) 下 DNP 中的交换 (J) 和偶极耦合 (D)，并提高了对超精细 DNP 光谱测量过渡金属 - 核自旋距离的潜力和范围的理解。这些研究揭示了新的 DNP 机制和新颖性。将 DNP 扩展到 S=1/2 以上的自旋系统的实验方法是通过开发并发电子 (e) 和核 (n) 自旋共振激发和检测的创新仪器功能来实现的；在静态和 MAS 条件下实现相干和/或自旋动力学辅助 e-n 偏振转移；以及双频泵浦探针二维电子双共振 (ELDOR)。该奖项反映了 NSF 的法定使命，并通过使用评估被认为值得支持基金会的智力价值和更广泛的影响审查标准。