DIRECT MEASUREMENT OF MULTIPLE QUANTUM RELAXATION TIME

A multiple quantum coherence （MQC） with a given order subjected to its own relaxa-tion decay in the evolution period can be transferred into observable single quantum （SQ）coherences in the detection period, the MQ relaxation time in a spin system, therefore, canbe directly measured by the 1-dimensional （1-D） Hahn echo method since the amplitudes ofSQC’s are modulated by the decayed MQC. This 1-D approach is an alternation to the 2-Dmeasurement for MQ relaxation time, the latter being somewhat time-consuming. The 1-Dapproaches can readily get rid of the inhomogeneous broadening of MQ lines. A method forselective measurement of various MQ relaxation times in AXsystems （n=1,2, and 3） witha given MQ order is presented. Consequently, the cross correlation coefficients of the sys-tems, which are not accessible in the SQ relaxation study, can be determined.