Vinogradov Elena, Madhu P K, Vega Shimon
Radiology Department, The Beth Israel Deaconess Medical Center, 330 Brookline Avenue, 02215, Boston, MA, USA.
Top Curr Chem. 2005;246:33-90. doi: 10.1007/b98648.
We describe radiofrequency (RF) pulse schemes in solid-state NMR applied to samples rotating at the magic angle (MAS) to obtain high-resolution (1)H spectra. Without combined RF schemes and MAS, (1)H spectra are normally severely broadened by the strong homonuclear proton-proton dipolar couplings. This review gives an outline of a representative class of multiple-pulse sequences, designed to work with and without MAS, and commonly used for high-resolution proton spectroscopy in solid-state NMR. We give a theoretical treatment of these sequences based on Floquet theory, both single-mode and bimodal. Using this approach, we define first-order homonuclear decoupling efficiency parameters which provide the line-narrowing characteristics of the various pulse sequences when applied to fast rotating samples. These parameters are used to compare the line-narrowing efficiencies of the multiple-pulse schemes.
我们描述了应用于在魔角旋转（MAS）的样品的固态核磁共振中的射频（RF）脉冲序列，以获得高分辨率的¹H谱。如果没有组合的RF序列和MAS，¹H谱通常会因强烈的同核质子 - 质子偶极耦合而严重展宽。本综述概述了一类代表性的多脉冲序列，这些序列设计为可在有或没有MAS的情况下工作，并且通常用于固态核磁共振中的高分辨率质子光谱学。我们基于弗洛凯理论对这些序列进行了理论处理，包括单模和双模。使用这种方法，我们定义了一阶同核去耦效率参数，这些参数在应用于快速旋转样品时提供了各种脉冲序列的线宽变窄特性。这些参数用于比较多脉冲方案的线宽变窄效率。
