R sequences for the scalar-coupling mediated homonuclear correlation spectroscopy under fast magic-angle spinning

High efficiency of homonuclear polarization transfer via scalar spin–spin coupling is achieved using a pulse sequence designed based on R pulse symmetry. Numerical simulations show that this new pulse sequence is robust with respect to rf inhomogeneity and resonance offsets. The required rf nutation frequency is five times the spinning frequency. Experimental data obtained for Ag4P2S6-II indicate that the new pulse sequence has a maximum efficiency about 75% and therefore is very promising for the measurement of homonuclear correlation spectra.