Radiofrequency fields in MAS solid state NMR probes
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F17%3A10367811" target="_blank" >RIV/00216208:11310/17:10367811 - isvavai.cz</a>
Result on the web
<a href="http://dx.doi.org/10.1016/j.jmr.2017.09.002" target="_blank" >http://dx.doi.org/10.1016/j.jmr.2017.09.002</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.jmr.2017.09.002" target="_blank" >10.1016/j.jmr.2017.09.002</a>
Alternative languages
Result language
angličtina
Original language name
Radiofrequency fields in MAS solid state NMR probes
Original language description
We present a detailed analysis of the radiofrequency (RF) field over full volume of a rotor that is generated in a solenoid coil. On top of the usually considered static distribution of amplitudes along the coil axis we describe dynamic radial RF inhomogeneities induced by sample rotation. During magic angle spinning (MAS), the mechanical rotation of the sample about the magic angle, a spin packet travels through areas of different RF fields and experiences periodical modulations of both the RF amplitude and the phase. These modulations become particularly severe at the end regions of the coil where the relative RF amplitude varies up to +/- 25% and the RF phase changes within +/- 30 degrees. Using extensive numerical simulations we demonstrate effects of RF inhomogeneity on pulse calibration and for the ramped CP experiment performed at a wide range of MAS rates. In addition, we review various methods to map RF fields using a B-0 gradient along the sample (rotor axis) for imaging purposes. Under such a gradient, a nutation experiment provides directly the RF amplitude distribution, a cross polarization experiment images the correlation of the RF fields on the two channels according to the Hartmann-Hahn matching condition, while a spin-lock experiment allows to calibrate the RF amplitude employing the rotary resonance recoupling condition. Knowledge of the RF field distribution in a coil provides key to understand its effects on performance of a pulse sequence at the spectrometer and enables to set robustness requirements in the experimental design.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Magnetic Resonance
ISSN
1090-7807
e-ISSN
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Volume of the periodical
284
Issue of the periodical within the volume
November
Country of publishing house
US - UNITED STATES
Number of pages
13
Pages from-to
20-32
UT code for WoS article
000414889800004
EID of the result in the Scopus database
2-s2.0-85029693516