Abstract: The sample rapid spinning about an axis inclined at "The Magic Angle", i.e.β_M=cos^-1(1)/√3 to the applied magnetic field(MAS)can eliminate many spe-ctral broadenings in solid NMR. The major anisotropic interactions in solids, namely Dipole-Dipole,Nuclear Quadrupole,Spin-spin or Indirect Dipole-dipole and Chemical Shift interaction and their effects on the NMR spectral broadening are reviewed firstly and then the influences of MAS on those interactions are treated by the averaging Hamiltonian theory.
MAS is the only one which can remove the shift anisotropy among the present high resolution methods in solid NMR,i.e. Multiple Pulses (MP).Multiple Quantum Transition (MQ), Cross Polarization and Heteronuclear High Power Decoupling (CP),and MAS itself as well. Consequently, MAS is the ultimate means for the liquid-like high resolution spectra in solids. The high resolution NMR in solids is now booming by the combinations of the above mentioned tech-niqes in a certain sense and by the wide spread applications of them.
Both the prime and the latest literatures are extensively reviewed and an effort is made to cover the most developments up to date,emphasizing the theoretical and the experimental aspects on the field in the paper.