Proton MAS NMR spectra at high magnetic fields and high spinning frequencies: Spectral simulations using Floquet theory

Proton magic angle spinning (MAS) spectra of a model spin system, consistin g of six protons, were calculated for different values of the external magn etic field and the spinning frequencies. Floquet theory was used to evaluat e these spectra. The reduction of the effective homonuclear dipolar interac tion for increasing spinning frequency was investigated. The influence of a n increase of the external magnetic field and the spinning frequencies on t he linewidths of the centerband spectra is discussed. This Floquet descript ion of the rotating proton spin system will assist us in our calculations o f the CPMAS spin dynamics of a low abundant spin interacting with a set of coupled protons. (C) 1998 Academic Press.