Efficient 1H-1H magnetization mixing at ultrafast MAS
Homonuclear dipolar interactions should be recoupled to achieve 1H-1H magnetization mixing at ultrafast MAS where the dipolar interactions are largely suppressed. Radio Frequency Driven Recoupling (RFDR) is widely used zero-quantum dipolar recoupling method for 13C and can be used for 1H as well. While (XY8)41 is the best phase cycling for 13C, it is not obvious what is the best for 1H. There is two criteria: 1) better conservation of overall 1H magnetization and 2) efficient magnetization transfer between 1Hs. The best is found to be XY4 for low power (～100 kHz) and XY414 for high power (～400 kHz).
ReferenceY. Nishiyama, R. Zhang, A. Ramamoorthy, J. Magn. Reson. 243 (2014) 25-32
*This research was supported by funds from NIH (GM084018 and GM095640 to Prof. A. Ramamoorthy).