Fig. 3.

Panel A shows the build up of cross-peak, indirect evolution on C_α and direct evolution on CO, (obtained from the experiment shown in Panel A for Fig. 2) as a function of the mixing time in units of number of rotor period (rotor period is 125 μs). Panel B shows the transfer efficiency as function of rf-power variation. Panel C shows the build up of Gamma-Prep peak, indirect evolution on CO and direct evolution on C_α, as the function of the mixing time in units of number of rotor periods. Panel D compared the height of cross-peaks for the PAMORE and gamma-prepared PAMORE, where the mixing time is 9 and 7 rotor periods, respectively. The mixing period is chosen from individual build up curves to give the best transfer efficiency. The spectrum for the PAMORE experiment uses the States method to combine the two quadrature components in the indirect dimension. Gamma-Prep PAMORE experiment is processed using echo/anti-echo as shown in Fig. 2C. The PAMORE mixing block was designed for a nominal power of 48 kHz, which is then experimentally optimized to maximize transfer efficiency. The carrier is placed at the CO resonance. Uniformly ¹³C, ¹⁵N-labeled sample of glycine was used in the full volume of standard 4 mm rotor at ambient temperature.