In solids, high-resolution NMR spectra are generally obtained while spinning the sample rapidly about the magic angle (MAS), with respect to an external satic magnetic field Bo. To enhance the spectrla sensitivity of rare, low-gamma nuclei, MAS is combined eith cross-polarization (CP) from abundant protons.

To first order, MAS suppresses the effect of anisotropic spin interactions, such as chemical-shift anisotropies (CSA) and dipole-dipole couplings. If the sample rotation speed is slower than the magnitude of the anisotropy of the interaction, a set of equally spaced peaks (called spinning sidebands) are observed in the spectrum. The spacing between each pair of epaks is equal to the sample rotation speed, whereas the frequency spacing between the left- and the right most sidebands, as well as the individual sideband samplitudes, are functions of the CSA interaction. If the spinning frequency is larger than the anisotropy of the interaction, only one pak at theisotropic value is observed.

Solid-State NMR
  • ssNMR Basics and principles
  • ssNMR Parameters and applications
  • ssNMR: Protein NMR
  • BRUKER manuals
  • ssNMR Tutorials
  • ssNMR Spectra
    • ssNMR Experiments
  • Basic ssNMR Experiments
  • Measurement of dipolar couplings and Decoupling
  • Correlation experiments
  • Half-integer Quadrupolar experiments
  • Exchange experiments

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