NEW NMR METHOD FOR THE INVESTIGATION OF T HE LOCAL DYNAMICS OF MOLECULES IN THE LIQUID-STATE

The steady-state magnetization of homonuclear spins, under strong off- resonance rf irradiation, is aligned with the effective field in the r otating frame. Its amplitude is a function of the angle between the ef fective and static fields, and of the dynamics of the system. For pure ly dipolar relaxation and isotropic Brownian rotation, it corresponds to an analytic form. When this law is verified experimentally, it yiel ds an effective local correlation time, that can be used for internucl ear distance determinations by the NOESY method. The experimental inad equacy of this law is indicative of complex local motions or extra rel axation mechanisms.