A new broadband homonuclear mixing pulse for NMR with low applied power.

Abstract

Broadband homonuclear mixing pulses with low radiofrequency power are essential for NMR spectroscopy of proteins and small molecules, especially for emerging applications in high field NMR. We have analytically designed a mixing pulse with high bandwidth-to-power ratio, using our recently developed multi-frame method. Here, we compare the new pulse, NF4 (mixing in the fourth nutating frame), to the best currently available sequence, focusing on the low-power regime. We use simulations and experiments to compare the two pulses' relaxation properties and bandwidth, and demonstrate that NF4 has approximately 1.35 times higher bandwidth, with similar effective relaxation. Therefore, NF4 is a good choice for broadband homonuclear mixing, particularly when the available radiofrequency power is limited.