With support from the Chemical Measurement and Imaging Program, Profs. Alexander Pines and Dmitry Budker and their groups at the University of California - Berkeley are developing nuclear magnetic resonance (NMR) in zero magnetic field as a subject of basic research and as a practical tool in chemistry and materials science. This work will uncover new phenomena in magnetic resonance and will eventually free NMR from its reliance upon externally imposed magnetic fields, leading to new technologies in portable NMR for chemical analysis and imaging. At zero magnetic field, nuclear spins in isotropic liquid samples evolve only under the electron mediated scalar couplings (J-couplings) between spins. Despite the absence of chemical shift information in zero-field NMR, the J-couplings are very sensitive to subtle changes in geometry and electronic structure and are thus a source of precise chemical information. As such, a primary goal of this research program is the demonstration of zero-field NMR J-spectroscopy as a technique for high-precision chemical fingerprinting and analysis. Furthermore, in order to disentangle chemical information from complex spectra, efforts will focus on the development of multi-pulse sequences for decoupling and recoupling specific heteronuclear and homonuclear couplings in zero-field multidimensional spectroscopy. This will involve advances in instrumentation and development of a theoretical understanding of average Hamiltonian theory and coherence transfer in the isotropic zero-field environment, as the symmetries are fundamentally different from those encountered in high-field NMR. The research program will also investigate nuclear-spin singlet state dynamics at zero magnetic field as a subject of basic research that will provide insight for the implementation of long-lived hyperpolarized states for biomedical applications.
NMR is a widely used technique in the physical and biological sciences for chemical detection, characterization, and structure elucidation. It is also the basis of magnetic resonance imaging (MRI). This research program is expanding the capabilities of NMR by moving in a new direction; one that does not require costly and immobile superconducting magnets. By employing sensitive atomic magnetometers to measure NMR signals, this work will enable portable and low-cost zero-field magnetic resonance sensors with potential applications ranging from environmental testing to geophysical and space research to medicine to fundamental physics. This project is providing training to graduate and undergraduate students in multiple disciplines, as well as mentoring for postdoctoral researchers, and is catalyzing research collaborations with scientists from the USA and abroad.
