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Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation

Coherence between tunnel-split states of a methyl quantum rotor can be generated and observed in stimulated and spin-locked echo experiments, if hyperfine coupling of a nearby electron spin to the methyl protons breaks C[Formula: see text] symmetry and is of the same order of magnitude as the tunnel...

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Autor principal: Jeschke, Gunnar
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Vienna 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9012728/
https://www.ncbi.nlm.nih.gov/pubmed/35509368
http://dx.doi.org/10.1007/s00723-021-01375-6
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author Jeschke, Gunnar
author_facet Jeschke, Gunnar
author_sort Jeschke, Gunnar
collection PubMed
description Coherence between tunnel-split states of a methyl quantum rotor can be generated and observed in stimulated and spin-locked echo experiments, if hyperfine coupling of a nearby electron spin to the methyl protons breaks C[Formula: see text] symmetry and is of the same order of magnitude as the tunnel splitting. Here, we consider the case of two methyl groups bound to the same sp[Formula: see text] -hybridized atom, which is important in the context of common nitroxide spin labels. For a simple form of the rotor-rotor coupling Hamiltonian, we provide an approach that allows for density operator computations of this system with 1152 quantum states with moderate computational effort. We find that, in the regime where the ratio between rotor-rotor coupling and rotational barrier is much smaller than unity, three-pulse ESEEM and hyperfine-decoupled ESEEM depend only on the tunnel splitting, but not on this ratio. This finding may simplify the treatment of tunnel-induced electron decoherence in systems where the methyl groups are bound to sp[Formula: see text] -hybridized atoms.
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spelling pubmed-90127282022-05-02 Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation Jeschke, Gunnar Appl Magn Reson Original Paper Coherence between tunnel-split states of a methyl quantum rotor can be generated and observed in stimulated and spin-locked echo experiments, if hyperfine coupling of a nearby electron spin to the methyl protons breaks C[Formula: see text] symmetry and is of the same order of magnitude as the tunnel splitting. Here, we consider the case of two methyl groups bound to the same sp[Formula: see text] -hybridized atom, which is important in the context of common nitroxide spin labels. For a simple form of the rotor-rotor coupling Hamiltonian, we provide an approach that allows for density operator computations of this system with 1152 quantum states with moderate computational effort. We find that, in the regime where the ratio between rotor-rotor coupling and rotational barrier is much smaller than unity, three-pulse ESEEM and hyperfine-decoupled ESEEM depend only on the tunnel splitting, but not on this ratio. This finding may simplify the treatment of tunnel-induced electron decoherence in systems where the methyl groups are bound to sp[Formula: see text] -hybridized atoms. Springer Vienna 2021-07-14 2022 /pmc/articles/PMC9012728/ /pubmed/35509368 http://dx.doi.org/10.1007/s00723-021-01375-6 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Original Paper
Jeschke, Gunnar
Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title_full Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title_fullStr Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title_full_unstemmed Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title_short Rotational Coupling in Methyl-Tunneling Electron Spin Echo Envelope Modulation
title_sort rotational coupling in methyl-tunneling electron spin echo envelope modulation
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9012728/
https://www.ncbi.nlm.nih.gov/pubmed/35509368
http://dx.doi.org/10.1007/s00723-021-01375-6
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