Articles | Volume 6, issue 1
https://doi.org/10.5194/mr-6-33-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Collection:
https://doi.org/10.5194/mr-6-33-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Increased sensitivity in electron–nuclear double resonance spectroscopy with chirped radiofrequency pulses
Julian Stropp
Institute for Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
Nino Wili
Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
Daniel Klose
CORRESPONDING AUTHOR
Institute for Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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Dynamic nuclear polarisation (DNP) transfers polarisation from electron to nuclear spins. This is usually combined with direct detection of the latter. Here, we show that it is possible to reverse the transfer at 1.2 T. This allows us to investigate the spin dynamics of nuclear spins close to electrons – something that is notoriously difficult with established methods. We expect reverse DNP to be useful in the study of spin diffusion or as a building block for more elaborate pulse sequences.
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Short summary
Sensitivity is often a limiting factor in electron–nuclear double resonance (ENDOR). Here we demonstrate how using chirp radiofrequency pulses can improve ENDOR sensitivity up to 3–9 fold, with the strongest increase for broader lines often encountered in disordered solids for nuclei such as nitrogen and metals. The resulting drastic speedup in acquisition times also renders 2D ENDOR more feasible, as we demonstrate in TRIPLE, showing correlations with Cu hyperfine couplings.
Sensitivity is often a limiting factor in electron–nuclear double resonance (ENDOR). Here we...
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