EXAMINATION OF HOMOGENEOUS BROADENING IN SOLIDS VIA ROTATIONALLY SYNCHRONIZED SPIN-ECHO NMR-SPECTROSCOPY

Carbon linewidths of 0.8 and 1.3 Hz have been measured for the aromatic and methyl resonances of polycrystalline hexamethylbenzene. These extremely narrow linewidths are obtained with a modified rotationally synchronized spin-echo experiment. The modifications include the use of composite pulses in the echo train to refocus magnetization and the use of additional phase cycling to remove unwanted transients. This experiment refocuses inhomogeneous contributions to the 13C linewidth and permits one to examine homogeneous contributions to the line-width, such as those arising from molecular motion. © 1993 by Academic Press, Inc.