Collaborative Research: DNP-Enhanced Nuclear-Spin Optical-Rotation Spectroscopy
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CHE-1404529 and CHE-1404548: Collaborative Research: DNP-Enhanced Nuclear-Spin Optical-Rotation SpectroscopyIn this project funded by the Chemical Measurement and Imaging Program of the Chemistry Division, Dr. Igor Savukov of the New Mexico Consortium and Professor Christian B. Hilty of Texas A & M University are collaboratively developing nuclear-spin optical rotation methodology for enhancing the information content in optical and nuclear magnetic resonance spectroscopy. The technique correlates nuclear spin states and electronic structure through dynamic vector polarizability. The severe obstacle for meaningful application is that the measured effect is normally extremely small, requiring substantial time for detection, even in water with very large concentration of protons. Progress in the application of nuclear-spin optical rotation to chemistry critically depends on strategies for signal enhancement. Compared to current methods, large improvements are needed for spectroscopy applications in dilute samples or samples with multiple peaks. Here, dynamic nuclear polarization is used to generate non-equilibrium nuclear spin states. Hyperpolarized samples can increase the nuclear-spin optical rotation signal 100-100,000 times, depending on the nuclei and experimental conditions and enable application of the method for the characterization of various chemical compounds. This new spectroscopic technique is being developed in three steps. First, nuclear-spin optical rotation of samples hyperpolarized by dynamic nuclear polarization is demonstrated. Second, the enhancement effect is characterized for various previously inaccessible nuclei and molecules, and results are compared with theory. Third, the technique is applied to the characterization of electronic structure in dye molecules. In the long term, the realization of this new spectroscopy offers a powerful analytical method for fundamental studies of light-matter interaction in liquids.The electronic structure of a molecule, both in ground and excited states, determines its basic molecular properties and reactivity. Measurements of electronic structure are necessary to understand the behavior of molecules in chemical reactions and other interactions. In this project, a new type of spectroscopy is being developed that is uniquely suited to probe spatially localized excited-state configurations of electrons. This spectroscopy is based on the measurement of an optical signal that is correlated to specific atoms in the molecule via the recently discovered nuclear-spin optical rotation effect. The project includes educational activities through a partnership between the New Mexico Consortium and Texas A&M University. Early-career scientists, including graduate an undergraduate students are being mentored, and the results from this research are incorporated into lecture classes.
