Nuclear Magnetic Resonance Methods for Non-Crystalline Solids

在这个由化学系化学测量和成像计划资助的项目中，俄亥俄州立大学的菲利普·格兰迪内蒂教授将开发新的核磁共振(核磁共振)方法来阐明非晶体材料的结构。在这些材料中，关于不同水平的原子结构有许多悬而未决的问题，从短程，即第一配位球结构分布，到中程，例如链和环的大小统计。核磁共振有可能提供所有这些水平的信息，无论是单独提供，还是由其他测量或建模补充。然而，要做到这一点，需要做大量的工作来建立方法的基础设施，并充分了解核磁共振参数和结构之间的关系。本项目所获得的结构分布对于确定玻璃和熔体的热力学模型、离子输运模型以及在玻璃结构和动力学的分子动力学模拟中提炼势能将是有价值的。这些细节可能会产生深远的影响。例如，放射性废物通常被混合到玻璃熔体中进行长期遏制，环境政策决定将需要关于玻璃作为存储材料的长期有效性的准确科学数据，这反过来又需要更深入地了解在很大程度上取决于原子级结构的运输性质。这些新的方法还将影响其他领域，如陶瓷、催化剂、生物聚合物，这些领域可以利用为我们的应用开发的相同资源和方法。该项目的长期目标是为材料科学家创建标准的核磁共振协议和软件，使他们能够获得足够的原子和分子级结构统计数据，以设计和合成新材料。除了材料科学的应用，该项目开发的固体中四极核的选择性核磁共振激发方法甚至可以用于磁共振成像的对比，并最终可能导致改进医学诊断和治疗。因此，可以预期这些磁共振方法中的许多将被整合到商业产品中。在这个项目中接受培训的学生包括代表人数不足的各种群体的成员。

In this project, funded by the Chemical Measurement and Imaging Program of the Chemistry Division, Professor Philip Grandinetti of the Ohio State University will develop new nuclear magnetic resonance (NMR) methods for elucidating structure in non-crystalline materials. There are many unresolved questions in these materials regarding atomic structure at different levels, from short range, i.e., first coordination sphere structural distributions, to intermediate range, e.g., chain and ring size statistics. It is possible for NMR to provide information at all these levels, either alone, or complemented by other measurements or modeling. To do this, however, much work is needed to build up an infrastructure of methods and a full understanding of the relationships between NMR parameters and structure. Structural distributions obtained in this project will be valuable in confirming thermodynamic models of glasses and melts, models for ionic transport, and also in refining potentials in molecular dynamics simulations of structure and dynamics in glasses. Such details can have far reaching impact. For example, radioactive waste is commonly mixed into glass melts for long term containment, and environmental policy decisions will require accurate scientific data on the long term effectiveness of glass as a storage material, which in turn, will require a deeper understanding of transport properties that depends strongly on the atomic level structure. These new methodologies will also impact other fields such as ceramics, catalysts, biopolymers, which can utilize the same resources and methodology developed for our applications. The long term goal of this project is to create standard NMR protocols and software for materials scientists enabling them to obtain enough atomic and molecular level structure statistics to design and synthesize new materials. Beyond materials science applications, methods developed in this project for selective NMR excitation of quadrupolar nuclei in solids can even be used for contrast in magnetic resonance imaging, and could eventually lead to improved medical diagnosis and treatment. As such, one can expect a number of these magnetic resonance methodologies to be incorporated into commercial products. Students trained in this project include members of various under-represented groups.