Role of quantum coherence in chirped dynamic nuclear polarization.

Dynamic Nuclear Polarization (DNP) is transforming nuclear magnetic resonance and MRI by significantly enhancing sensitivity through the transfer of polarization from electron spins to nuclear spins via microwave irradiation. However, the use of monochromatic continuous-wave irradiation limits the efficiency of DNP for systems with heterogeneous, broad electron paramagnetic resonance lines. Broadband techniques such as chirp irradiation offer a potential solution, particularly for Solid Effect (SE) DNP in such cases.

Microwave-free nuclear spin hyperpolarization through photo-CIDNP in static and rotating solids.

This study advances the theoretical foundation of photo-chemically induced dynamic nuclear polarization (photo-CIDNP)-a powerful mechanism for enhancing nuclear spin sensitivity without microwave irradiation. Using an operator-based effective Hamiltonian approach, we derive precise resonance matching conditions and identify key dipolar scaling factors governing the photo-CIDNP Hamiltonian under both static and magic-angle spinning conditions. Our analytical formulation of coherent evolution of photoexcited singlet state exhibits strong agreement with numerical simulations, reinforcing the validity of our theoretical framework.