Nuclear magnetic resonance spectroscopy of disordered solids

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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.