Proton dipolar spinning-sideband intensities in the MAS NMR spectrum of a solid containing a molecular group with fast anisotropic rotation

An expression for the proton dipolar spinning-sideband intensities in MAS NMR spectra has been derived for a solid containing molecules and/or groups with fast axial rotation. It is shown that the sideband intensities are linear with the even-order moments of the dipolar interaction. The theoretical expressions have been confirmed by comparing the calculated and measured sideband intensities for powdered crystalline hexamethylbenzene.