Centre de RMN à Très Hauts Champs, FRE 3008 CNRS/Ecole Normale Supérieure de Lyon/Université Claude Bernard Lyon 1, 69100 Villeurbanne, France.
J Chem Phys. 2011 Jan 14;134(2):024117. doi: 10.1063/1.3521491.
We explain how and under which conditions it is possible to obtain an efficient inversion of an entire sideband family of several hundred kHz using low-power, sideband-selective adiabatic pulses, and we illustrate with some experimental results how this framework opens new avenues in solid-state NMR for manipulating spin systems with wide spinning-sideband (SSB) manifolds. This is achieved through the definition of the criteria of phase and amplitude modulation for designing an adiabatic inversion pulse for rotating solids. In turn, this is based on a framework for representing the Hamiltonian of the spin system in an NMR experiment under magic angle spinning (MAS). Following earlier ideas from Caravatti et al. [J. Magn. Reson. 55, 88 (1983)], the so-called "jolting frame" is used, which is the interaction frame of the anisotropic interaction giving rise to the SSB manifold. In the jolting frame, the shift modulation affecting the nuclear spin is removed, while the Hamiltonian corresponding to the RF field is frequency modulated and acquires a spinning-sideband pattern, specific for each crystallite orientation.
我们解释了如何以及在什么条件下可以使用低功率、边带选择绝热脉冲有效地反转几百千赫兹的整个边带族，并通过一些实验结果说明了这一框架如何为固态 NMR 中操纵具有宽旋转边带（SSB）谱的自旋系统开辟新的途径。这是通过为旋转固体设计绝热反转脉冲来定义相位和幅度调制的标准来实现的。反过来，这是基于在魔角旋转（MAS）下 NMR 实验中表示自旋系统哈密顿量的框架。继 Caravatti 等人的早期思想[J. Magn. Reson. 55, 88 (1983)]之后，使用了所谓的“抖动框架”，它是产生 SSB 谱的各向异性相互作用的相互作用框架。在抖动框架中，去除了影响核自旋的位移调制，而对应于射频场的哈密顿量则被频率调制，并获得了特定于每个晶粒度取向的旋转边带图案。
