Magnetic resonance studies of molecular structure and dynamics

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Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) will be used to provide insights into important problems in chemistry, materials science and engineering. We are particularly interested in gaining a better understanding of the relationship between the fundamental parameters that one measures in an NMR experiment and molecular structure. We will take advantage of the fact that NMR studies of solid materials provide one with an opportunity to characterize the tensors that describe these parameters instead of their isotropic values. Considerable effort will be devoted to NMR investigations of paramagnetic solids such as contrast agents used in MRI. The information available from such studies as well as the limitations of modern techniques in probing these materials is not well understood. We will use the National Ultrahigh-Field NMR Facility for Solids to explore the potential of high-field NMR spectroscopy, particularly in studying important non-integer spin quadrupolar nuclei that have not been well studied (e.g., As-75, Sb-121). Our recent successful applications of NMR microscopy to study water distribution in operating polymer electrolyte fuel cells will be extended. Immediate goals include: improving the spatial resolution of our 1H NMR images, improving water quantification, detecting water in the graphite-felt gas diffusion layer and extending our methodology to alcohol fuel cells. Knowledge of water distribution in operating fuel cells is absolutely critical in developing more reliable polymer electrolyte fuel cell models. Our NMR investigations of porous materials using thermally polarized and hyperpolarized Xe-129 NMR studies will continue. In collaboration with Steve Kuznicki, a CRC in Molecular Sieve Nanomaterials, we are using Xe-129 NMR as well as Al-27, Si-29 and Ag-109 NMR to examine a number of potentially important silver-exchanged molecular sieves that have applications that include argon-oxygen gas separation. Finally, we will be working independently and in collaboration with Paul Callaghan at Victoria University in Wellington, New Zealand to develop applications of NMR in the Earth's magnetic field.