EXPERIMENTAL-DETERMINATION OF 4-TIME STIMULATED ECHOES IN LIQUIDS, COLLOIDAL SUSPENSIONS, AND CRYSTALS

Four-time stimulated echo experiments have been used to monitor the te mporal evolution of the reorientation rates of deuterated molecules or colloidal suspensions. We present extended phase cycles for this seve n-pulse experiment. In order to test its performance three vastly diff erent materials are chosen. These include a crystal in which the molec ules carry out well-defined 180 degrees flips and a supercooled liquid characterized by a distribution of jump angles centered around 10 deg rees. As an example for rotational diffusion, data on a concentrated s uspension of polystyrene spheres in a viscous medium are presented. (C ) 1998 Academic Press.