Time-optimized pulsed dynamic nuclear polarization
Author(s)Tan, Kong Ooi; Yang, Chen; Mathies, Guinevere; Griffin, Robert Guy
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Pulsed dynamic nuclear polarization (DNP) techniques can accomplish electron-nuclear polarization transfer efficiently with an enhancement factor that is independent of the Zeeman field. However, they often require large Rabi frequencies and, therefore, high-power microwave irradiation. Here, we propose a new low-power DNP sequence for static samples that is composed of a train of microwave pulses of length t p spaced with delays d. A particularly robust DNP condition using a period t m = t p + d set to ~1.25 times the Larmor period t Larmor is investigated which is a time-optimized pulsed DNP sequence (TOP-DNP). At 0.35 T, we obtained an enhancement of ~200 using TOP-DNP compared to ~172 with nuclear spin orientation via electron spin locking (NOVEL), a commonly used pulsed DNP sequence, while using only ~7% microwave power required for NOVEL. Experimental data and simulations at higher fields suggest a field-independent enhancement factor, as predicted by the effective Hamiltonian.
DepartmentMassachusetts Institute of Technology. Department of Chemistry
American Association for the Advancement of Science (AAAS)
Tan, Kong Ooi et al. “Time-optimized pulsed dynamic nuclear polarization.” Science Advances, vol. 5, 2019, eaav6909 © 2019 The Author(s)
Final published version