Nuclear magnetic resonance spectroscopy of disordered solids

由于无序性，玻璃的分子水平结构本身就难以研究。核磁共振（NMR）光谱学特别适合于研究无序固体，因为它主要对给定核的局部环境敏感。我们将使用核磁共振来研究核废料玻璃。要研制出耐用到足以容纳放射性废物离子数千年的玻璃，就需要对这些离子在玻璃中的结合方式有详细而可靠的了解。核磁共振将提供关于废离子在玻璃网络中的位置的结构信息，以及它们是否会分离成不那么持久的相。高温核磁共振也将告知在玻璃凝固过程中不同相的分离，以及如何通过添加其他元素来防止这种情况。这项工作的结果将是优化核废料玻璃耐久性的成分和工艺，并确保放射性废料产品安全地保存在地质储存库中。核磁共振还将用于研究离子导电玻璃，这种玻璃对更小、更便携和高容量的电池很有兴趣。高温核磁共振将用于表征离子通过玻璃网络的运动，并定义扩散通道的分子结构。这将使高性能材料的设计具有增强的离子电导率，同时保持化学耐久性。最后，我们将继续探索曾经被认为是“不可能”的系统的核磁共振可探测性的前沿，但现在有了新的方法和仪器。在这一领域的成功将扩大核磁共振的用途，以结构解析目前超出其能力范围的大量材料。

The molecular-level structure of glasses is inherently difficult to study because of disorder. Nuclear magnetic resonance (NMR) spectroscopy is uniquely suited for studying disordered solids because it is principally sensitive to the local environment about a given nucleus. We will use NMR to study nuclear waste glasses. The development of glasses durable enough to contain radioactive waste ions for millennia requires a detailed and reliable understanding of how these ions are bonded in the glass. NMR will provide structural information about where the waste ions are located in the glassy network, and whether they separate into less-durable phases. High-temperature NMR will also inform about the separation of different phases during glass solidification from the melt, and how to prevent this by the addition of other elements. The result of this work will be compositions and processes that optimize the durability of nuclear waste glasses and ensure that the radioactive waste products remain safely contained in geologic repositories. NMR will also be used to study ion-conducting glasses which are of interest for use in smaller, more portable and high-capacity batteries. High-temperature NMR will be used to characterize the movement of ions through a glassy network, and to define the molecular structure of the diffusion channels. This will enable the design of high-performance materials with enhanced ionic conductivity while maintaining chemical durability. Finally, we will continue to explore the frontiers of NMR detectability in systems once considered "impossible", but now are becoming accessible with new methodology and instrumentation. Success in this area will expand the utility of NMR for structural elucidation of a vast range of materials currently beyond its capability.