Homonuclear radio frequency-driven recoupling in rotating solids
Homonuclear radio frequency-driven recoupling in rotating solids
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DOI：
10.1063/1.476420
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发表时间：
1998-06-08
影响因子：
4.4
通讯作者：
Griffin, RG
中科院分区：
文献类型：
--
作者：
Bennett, AE;Rienstra, CM;Griffin, RG
我们讨论了固态魔角旋转（MAS）实验中使用转子同步自旋回波序列的同核重耦合和纵向交换的几个方面。这些包括精确测量稀有自旋之间的弱偶极-偶极耦合、偶极轨迹的行为：在多自旋环境中，以及通过偏振交换的化学位移相关光谱。为了准确地描述偶极轨迹，我们采用了模拟这些实验的方法。其中包括有限脉冲和相干衰变的影响，后一种效应在许多实验中与弱耦合的强度相竞争，并概述了一种简单的经验方法来选择衰变参数，通过比较两个和三个相互作用的自旋，偶极轨迹被证明是由多自旋系统中的最大耦合主导的基于邻近核之间偶极交换的二维相关光谱用统一的 N-15 C-13 标记的四肽样品来说明achatin-II（Gly-L-Phe-L-Ala-L-Asp）。此外，还引入了一种频率选择性方法来重新耦合同核自旋之间的偶极相互作用；：选择性方法在存在强相互作用的情况下检查弱偶极-偶极耦合可能有用。 (C) 1998 年美国物理研究所。
We discuss several aspects of homonuclear recoupling and longitudinal exchange using rotor-synchronized spin echo sequences in solid state magic-angle spinning (MAS),experiments. These include the accurate measurement Of weak dipole-dipole couplings between rare spins, the behavior of dipolar trajectories: in multiple spin environments, and chemical shift correlation spectroscopy via polarization exchange. To describe dipolar trajectories accurately,we adopt an approach to the simulation df these experiments. which includes finite pulses and the influence of coherence decay, The latter effect becomes competitive with the strength of weak couplings in many experiments, and a simple empirical approach is outlined for the selection of decay parameters, Dipolar trajectories are shown to be dominated by the largest couplings in multiple spin systems via comparison of two and three interacting spins Two-dimensional correlation spectroscopy based on dipolar exchange among proximate nuclei is illustrated with a uniformly N-15 C-13-labeled sample of the tetrapeptide achatin-II (Gly-L-Phe-L-Ala-L-Asp). In addition, a frequency-selective approach to recoupling dipolar interactions among homonuclear spins is introduced;: selective approaches have possible utility in examining weak dipole-dipole couplings in the presence of strong interactions. (C) 1998 American Institute of Physics.