FIG. 4.

Top: Experimental RFDR buildup curves for AGG-2, AGG-3, and GGV-3. Each data point is the integrated peak intensity of 2D correlation peaks normalized to the diagonal peak at zero mixing. RFDR experiments employed 50 kHz ${}^{13}\text{C}\pi$ pulses and 115 and 90 kHz ${}^1\text{H}$ decoupling fields during the mixing period and were performed at a MAS frequency of 8.929 kHz. Bottom: Numerical simulations of polarization transfer in AGG-2, AGG-3, and GGV-3 showing long-term behavior of RFDR mixing. These simulations included ${}^{13}\text{C}$ CSA parameters, eight neighboring ${}^1\text{H}$ spins, and experimental parameters identical to those performed in our experiments.