CAREER:Developing Novel Nuclear Magnetic Resonance Contrast and Sensitivity Enhancement Mechanisms for Materials and Reactions Studies

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Song-I Han of the University of California-Santa Barbara is supported by the Experimental Physical Chemistry Program to develop novel contrast mechanisms for nuclear magnetic resonance (NMR) that highlight molecule-specific functions of materials and processes by targeted signal enhancement of selected fluid molecules. Two different approaches for achieving non-equilibrium nuclear spin polarization will be pursued and developed, presenting mechanisms to obtain different types of contrast. One approach, utilizing inserted or natural unpaired electrons in solid matrices for NMR signal modulation, has not been demonstrated previously. In the research effort, (1) the widely used Overhauser effect will be extended to a broader range of nuclei and molecules, (2) a better understanding of the interactions between nuclei and unpaired electrons in materials will be achieved, (3) flow dispersion, absorption and reactivity of molecules in porous materials -- difficult properties to study-- will be accessed in situ, and (4) light will be shed on the whereabouts of active sites in heterogeneous catalysts. Theoretical efforts, instrumentation development utilizing emerging, high-power, microwave technology and the integration of interdisciplinary knowledge will be employed to meet the research aims.Novel contrast and higher sensitivity NMR as developed in this project will allow the exploitation of molecule-material interactions that are currently difficult to access. The developing capability to trace directly the transport and absorption of small molecules into porous media in situ is highly significant in a broad range of areas such as chemical reaction, biological function, drug delivery, and petroleum research. The educational project plan includes the organization of magnetic resonance based workshops and field studies for undergraduate and high school students that will give them the opportunity for hands-on learning about magnetic fields and how NMR can be used to learn about common materials in the environment.