Field-stepped ultra-wideline NMR at up to 36 T On the inequivalence between field and frequency stepping

Field-stepped ultra-wideline NMR at up to 36 T : On the inequivalence between field and frequency stepping

© 2020 John Wiley & Sons, Ltd.

Bibliographische Detailangaben
Veröffentlicht in:Magnetic resonance in chemistry : MRC. - 1985. - 59(2021), 9-10 vom: 03. Sept., Seite 951-960
1. Verfasser: Hung, Ivan (VerfasserIn)
Weitere Verfasser: Altenhof, Adam R, Schurko, Robert W, Bryce, David L, Han, Oc Hee, Gan, Zhehong
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2021
Zugriff auf das übergeordnete Werk:Magnetic resonance in chemistry : MRC
Schlagworte:Journal Article field stepping quadrupole nuclei simulations solid-state NMR wideline
Beschreibung
Zusammenfassung:© 2020 John Wiley & Sons, Ltd.
Field-stepped NMR spectroscopy at up to 36 T using the series-connected hybrid (SCH) magnet at the U.S. National High Magnetic Field Laboratory is demonstrated for acquiring ultra-wideline powder spectra of nuclei with very large quadrupolar interactions. Historically, NMR evolved from the continuous-wave (cw) field-swept method in the early days to the pulsed Fourier-transform method in the modern era. Spectra acquired using field sweeping are generally considered to be equivalent to those acquired using the pulsed method. Here, it is shown that field-stepped wideline spectra of half-integer spin quadrupolar nuclei acquired using WURST/CPMG methods can be significantly different from those acquired with the frequency-stepped method commonly used with superconducting magnets. The inequivalence arises from magnetic field-dependent NMR interactions such as the anisotropic chemical shift and second-order quadrupolar interactions; the latter is often the main interaction leading to ultra-wideline powder patterns of half-integer spin quadrupolar nuclei. This inequivalence needs be taken into account to accurately and correctly determine the quadrupolar coupling and chemical shift parameters. A simulation protocol is developed for spectral fitting to facilitate analysis of field-stepped ultra-wideline NMR spectra acquired using powered magnets. A MATLAB program which implements this protocol is available on request
Beschreibung:Date Completed 09.09.2021
Date Revised 07.11.2023
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1097-458X
DOI:10.1002/mrc.5128