text: The strong H-H homonuclear dipolar interactions associated with broad NMR lines and short T relaxation time effectively relegate proton for bimolecular NMR. Recent developments of faster MAS, and reduction of dipolar interactions by deuteration have made proton ssNMR as versatile as in solution. This includes spectral dispersion in multi-dimensional experiments as well as structurally valuable restraints and parameters important for studying material dynamics.
  Ultra-fast NMR and the associated sharpening of the NMR lines enables NMR pulse sequences to capitalize on proton-detection to improve the sensitivity of the experiments compared to the direct detection of a spin-1/2 system (X). Such enhancement factor  is given by:
  where  are the gyromagnetic ratios,  represent the NMR line widths, and  represent the quality factor of the probe resonances.