RF inhomogeneity and how it controls CPMAS.
作者： Rupal Gupta , Guangjin Hou , Tatyana Polenova , Alexander J. Vega
DOI: 10.1016/J.SSNMR.2015.09.005
关键词:
摘要: In this report we discuss the effect of radiofrequency field (RF) inhomogeneity on cross-polarization (CP) under magic-angle spinning (MAS) by reviewing dependence CP-detected signal intensity as a function position in sample space. We introduce power-function model to quantify position-dependent RF-amplitude profile. The applicability is experimentally verified nutation spectra obtained direct detection, well CPMAS two commercial MAS probes with different degrees RF inhomogeneity. A conclusion that substantial sections totally filled rotor, even probe rather good homogeneity, do not contribute at all detected spectra. consequence CPMAS-based recoupling experiments, such CP-with-variable-contact-time (CPVC), spatial selectivity Hartmann-Hahn matching condition overcomes complications could be caused permitting determination accurate spectral parameters cases high
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