Thermal relaxation and coherence dynamics of spin 3/2. II. Strong radio‐frequency field

The relaxation dynamics of the spin‐3/2 density operator under strong, on‐resonance radio‐frequency (RF) irradiation and in the presence of fluctuating and static quadrupolar interactions is reviewed. The evolution under the lock is analyzed for any value of the static quadrupolar interaction, ranging from isotropic systems to systems exhibiting large splitting far exceeding the line widths. For isotropic systems, relaxation under off‐resonance spin‐locking conditions and in the multiple‐pulse quadrupolar echo (QE) experiment is reviewed also. Spin‐lock pulse sequences optimized for the selective detection of nuclei involved in slow molecular motion and/or in anisotropic, liquid crystalline environment are discussed. In Part I, the classical relaxation dynamics of spin 3/2 was reviewed.