Theoretical analysis of scalar relaxation in 13C-DNP in liquids
Theoretical analysis of scalar relaxation in 13C-DNP in liquids
Dynamic nuclear polarization in the liquid state via Overhauser effect is enabled by the fluctuations of the electron-nuclear hyperfine interaction. Fermi contact (or scalar) hyperfine coupling can be modulated by molecular collisions on timescales of a few picoseconds and shorter, enabling an effective polarization transfer even at high magnetic fields. However, only a few studies have presented a theoretical analysis of the scalar mechanism. Here we report the current understanding of the scalar relaxation in liquid-state DNP and present different modeling strategies based on analytical relaxation theory and numerical calculations from molecular dynamics simulations. These approaches give consistent results in identifying the timescale of the fluctuations of the scalar interaction that drives 13C-DNP in the model system of CHCl3 doped with nitroxide radical. Subpicosecond fluctuations arise not only from random molecular collisions but are also present when target molecule and polarizing agent form a transient complex that persists for tens of picoseconds. We expect that these kind of interactions, possibly based on hydrogen bond-like complexations, might be present in a large variety of compounds.
Orlando, Tomas
aebe534b-c83e-4b0d-8c13-3a1fcfce0ab7
Kuprov, Ilya
bb07f28a-5038-4524-8146-e3fc8344c065
Hiller, Markus
db522858-37ba-4acf-9439-b16f60005bcd
Orlando, Tomas
aebe534b-c83e-4b0d-8c13-3a1fcfce0ab7
Kuprov, Ilya
bb07f28a-5038-4524-8146-e3fc8344c065
Hiller, Markus
db522858-37ba-4acf-9439-b16f60005bcd
Orlando, Tomas, Kuprov, Ilya and Hiller, Markus
(2022)
Theoretical analysis of scalar relaxation in 13C-DNP in liquids.
Journal of Magnetic Resonance Open, 10-11, [100040].
(doi:10.1016/j.jmro.2022.100040).
Abstract
Dynamic nuclear polarization in the liquid state via Overhauser effect is enabled by the fluctuations of the electron-nuclear hyperfine interaction. Fermi contact (or scalar) hyperfine coupling can be modulated by molecular collisions on timescales of a few picoseconds and shorter, enabling an effective polarization transfer even at high magnetic fields. However, only a few studies have presented a theoretical analysis of the scalar mechanism. Here we report the current understanding of the scalar relaxation in liquid-state DNP and present different modeling strategies based on analytical relaxation theory and numerical calculations from molecular dynamics simulations. These approaches give consistent results in identifying the timescale of the fluctuations of the scalar interaction that drives 13C-DNP in the model system of CHCl3 doped with nitroxide radical. Subpicosecond fluctuations arise not only from random molecular collisions but are also present when target molecule and polarizing agent form a transient complex that persists for tens of picoseconds. We expect that these kind of interactions, possibly based on hydrogen bond-like complexations, might be present in a large variety of compounds.
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Accepted/In Press date: 29 January 2022
e-pub ahead of print date: 1 February 2022
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Local EPrints ID: 455477
URI: http://eprints.soton.ac.uk/id/eprint/455477
ISSN: 2666-4410
PURE UUID: 2f79f2af-9b52-43fb-9961-0d1007bca6a4
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Date deposited: 22 Mar 2022 17:43
Last modified: 17 Mar 2024 03:28
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Author:
Tomas Orlando
Author:
Markus Hiller
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