Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)

<p>In this paper, we provide an analytical description of the performance of the cross-polarization (CP) experiment, including linear ramps and adiabatic tangential sweeps, using effective Hamiltonians and simple rotations in 3D space. It is shown that radiofrequency field inhomogeneity induce...

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Main Authors: A. Šmelko, J. Blahut, B. Reif, Z. Tošner
Format: Article
Language:English
Published: Copernicus Publications 2023-08-01
Series:Magnetic Resonance
Online Access:https://mr.copernicus.org/articles/4/199/2023/mr-4-199-2023.pdf
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author A. Šmelko
J. Blahut
B. Reif
B. Reif
Z. Tošner
author_facet A. Šmelko
J. Blahut
B. Reif
B. Reif
Z. Tošner
author_sort A. Šmelko
collection DOAJ
description <p>In this paper, we provide an analytical description of the performance of the cross-polarization (CP) experiment, including linear ramps and adiabatic tangential sweeps, using effective Hamiltonians and simple rotations in 3D space. It is shown that radiofrequency field inhomogeneity induces a reduction in the transfer efficiency at increasing magic angle spinning (MAS) frequencies for both the ramp and the adiabatic CP experiments. The effect depends on the ratio of the dipolar coupling constant and the sample rotation frequency. In particular, our simulations show that for small dipolar couplings (1 <span class="inline-formula">kHz</span>) and ultrafast MAS (above 100 <span class="inline-formula">kHz</span>) the transfer efficiency is below 40 % when extended contact times up to 20 <span class="inline-formula">ms</span> are used and relaxation losses are ignored. New recoupling and magnetization transfer techniques that are designed explicitly to account for inhomogeneous radiofrequency fields are needed.</p>
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spelling doaj.art-ff50dd9571cf42f18e1fa787a710f0492023-08-15T08:55:10ZengCopernicus PublicationsMagnetic Resonance2699-00162023-08-01419921510.5194/mr-4-199-2023Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)A. Šmelko0J. Blahut1B. Reif2B. Reif3Z. Tošner4Department of Chemistry, Faculty of Science, Charles University, Albertov 6, 12842 Prague, Czech RepublicInstitute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, 16610, Prague, Czech RepublicBayerisches NMR Zentrum (BNMRZ) at School of Natural Sciences, Department of Bioscience, Technische Universität München (TUM), Lichtenbergstr. 4, 85747 Garching, GermanyHelmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt, 85764 Neuherberg, GermanyDepartment of Chemistry, Faculty of Science, Charles University, Albertov 6, 12842 Prague, Czech Republic<p>In this paper, we provide an analytical description of the performance of the cross-polarization (CP) experiment, including linear ramps and adiabatic tangential sweeps, using effective Hamiltonians and simple rotations in 3D space. It is shown that radiofrequency field inhomogeneity induces a reduction in the transfer efficiency at increasing magic angle spinning (MAS) frequencies for both the ramp and the adiabatic CP experiments. The effect depends on the ratio of the dipolar coupling constant and the sample rotation frequency. In particular, our simulations show that for small dipolar couplings (1 <span class="inline-formula">kHz</span>) and ultrafast MAS (above 100 <span class="inline-formula">kHz</span>) the transfer efficiency is below 40 % when extended contact times up to 20 <span class="inline-formula">ms</span> are used and relaxation losses are ignored. New recoupling and magnetization transfer techniques that are designed explicitly to account for inhomogeneous radiofrequency fields are needed.</p>https://mr.copernicus.org/articles/4/199/2023/mr-4-199-2023.pdf
spellingShingle A. Šmelko
J. Blahut
B. Reif
B. Reif
Z. Tošner
Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
Magnetic Resonance
title Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
title_full Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
title_fullStr Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
title_full_unstemmed Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
title_short Performance of the cross-polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning (MAS)
title_sort performance of the cross polarization experiment in conditions of radiofrequency field inhomogeneity and slow to ultrafast magic angle spinning mas
url https://mr.copernicus.org/articles/4/199/2023/mr-4-199-2023.pdf
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