Imaging of the H NMR Second Moment with C Chemical-Shift Resolution

A method of ¹³C chemical-shift-resolved ¹H second moment imaging is proposed for molecular mobility imaging of heterogeneous materials. For evaluating the ¹H second moment, the method relies on the curve fitting procedure using spin-echo shapes indirectly: The information of ¹H echo shapes is transferred to the ¹³C signal amplitude through ¹H–¹³C cross polarization and then the curve fitting is made using the ¹³C signal amplitude. The ¹³C signal is detected under ¹H dipolar decoupling and magic angle spinning, resulting in the incorporation of ¹³C chemical-shift resolution. Imaging information is included in the ¹³C signal by application of phase-encoding gradients. The second moment images obtained can reflect the molecular mobility at every molecular site separated by ¹³C chemical shifts, yielding detailed information on the molecular mobility. The method is demonstrated by spatially 1D experiments performed on a model sample.