Numerical simulations of the anisotropic dimension of the Rotation-Induced Adiabatic Coherence Transfer RIACT MQ experiment have been performed as a function of the asymmetry parameter, h, for different spacings between the triple Ž . Ž . quantum 3Q excitation and 3Q to single quantum 1Q reconversion pulses. Large distortions of the spectra are observed, in comparison to the spectra obtained with 1D MAS NMR methods. The method is very sensitive to the relative orientation of the quadrupolar tensor and rotor axis, and signal can only be obtained from a maximum of 60% of the powder. The intensity varies with the spacing between the two pulses, t , reaching a minimum of 30% when t is either a multiple of a 1 1 Ž . Ž . Ž . full rotor period nt or for n q 1r2 rotor periods, for pulse lengths t of a quarter of a rotor period. The maximum of r 1SL
60% is obtained when t s nt y t . Experimental spectra were acquired for anhydrous Na HPO . Good fits were 1 r 1 S L 2 4
obtained between the experimental and simulated spectra, even for the non-rotor synchronized experiment, by choosing fixed values of t . The simulations allowed the quadrupole coupling constants and asymmetry parameters to be extracted from the 1 experimental data.