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Time-optimized pulsed dynamic nuclear polarization.

ABSTRACT: 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 ?_p spaced with delays d. A particularly robust DNP condition using a period ?_m = ?_p + d set to ~1.25 times the Larmor period ?_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.

SUBMITTER: Tan KO

PROVIDER: S-EPMC6357739 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Time-optimized pulsed dynamic nuclear polarization.

Tan Kong Ooi KO Yang Chen C Weber Ralph T RT Mathies Guinevere G Griffin Robert G RG

Science advances 20190118 1

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 τ<sub>p</sub> spaced with delays <i>d</i>. A particularly robust DNP condition using a pe ...[more]

PMID: 30746482

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