Department of Chemistry, University of York, YO10 5DD York, UK.
J Magn Reson. 2013 Mar;228:66-75. doi: 10.1016/j.jmr.2012.12.015. Epub 2013 Jan 5.
The use of genetic algorithms for the optimisation of magic angle spinning NMR pulse sequences is discussed. The discussion uses as an example the optimisation of the C7(2)(1) dipolar recoupling pulse sequence, aiming to achieve improved efficiency for spin systems characterised by large chemical shielding anisotropies and/or small dipolar coupling interactions. The optimised pulse sequence is found to be robust over a wide range of parameters, requires only minimal a priori knowledge of the spin system for experimental implementations with buildup rates being solely determined by the magnitude of the dipolar coupling interaction, but is found to be less broadbanded than the original C7(2)(1) pulse sequence. The optimised pulse sequence breaks the synchronicity between r.f. pulses and sample spinning.
讨论了遗传算法在魔角旋转 NMR 脉冲序列优化中的应用。该讨论以优化 C7(2)(1)偶极重聚脉冲序列为例，旨在为具有大的化学位移各向异性和/或小的偶极耦合相互作用的自旋系统实现更高的效率。优化后的脉冲序列在广泛的参数范围内具有稳健性，仅需要对自旋系统有最小的先验知识即可进行实验实现，且堆积速率仅由偶极耦合相互作用的大小决定，但发现其宽带性不如原始的 C7(2)(1)脉冲序列。优化后的脉冲序列打破了射频脉冲和样品旋转之间的同步性。
