Rotationally induced triple quantum coherence excitation in MAS NMR spectroscopy of I=5/2 spins

Rotationally induced excitation of triple quantum coherences is demonstrated unequivocally for I=5/2 nuclei from comparison of the variation of the observed and simulated lineshapes as a function of spin-lock time. A new pulse sequence is presented that produces purely absorptive lineshapes from such an experiment. An important observation is that the coherence transfer goes through a maximum at moderate rf fields.