Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
J Chem Phys. 2021 Sep 7;155(9):094202. doi: 10.1063/5.0061611.
Separation and correlation of the shift anisotropy and the first-order quadrupolar interaction of spin I = 1 nuclei under magic-angle spinning (MAS) are achieved by the phase-adjusted spinning sideband (PASS) nuclear magnetic resonance (NMR) experiment. Compared to methods for static samples, this approach has the benefit of higher sensitivity and resolution. Moreover, the PASS experiment has the advantage over previous MAS sequences in the ability to completely separate the shift anisotropy and first-order quadrupolar interactions. However, the main drawback of the pulse sequence is the lower excitation bandwidth. The sequence is comprehensively evaluated using theoretical calculations and numerical simulations and applied experimentally to the H NMR of a range of paramagnetic systems: deuterated nickel(II) acetate tetrahydrate, deuterated copper(II) chloride dihydrate, and two forms of deuterated oxyhydride ion conductor BaTiOH. Our results show that despite the issue with broadband excitation, the extracted shift and quadrupolar interaction tensors and the Euler angles relating the two tensors match well with the NMR parameters obtained with static NMR methods. Therefore, the new application of the PASS experiment is an excellent addition to the arsenal of NMR experiments for H and potentially N in paramagnetic solids.
通过相位调整旋转边带（PASS）核磁共振（NMR）实验，实现了魔角旋转（MAS）下自旋 I=1 核的位移各向异性和一级四极相互作用的分离和相关。与静态样品方法相比，这种方法具有更高的灵敏度和分辨率的优点。此外，与以前的 MAS 序列相比，PASS 实验具有完全分离位移各向异性和一级四极相互作用的优势。然而，该脉冲序列的主要缺点是激励带宽较低。该序列通过理论计算和数值模拟进行了全面评估，并应用于一系列顺磁体系的 H NMR 实验：氘代乙酸镍（II）四水合物、氘代氯化铜（II）二水合物和两种形式的氘代氧化氢离子导体 BaTiOH。结果表明，尽管宽带激励存在问题，但提取的位移和四极相互作用张量以及两个张量之间的欧拉角与使用静态 NMR 方法获得的 NMR 参数非常吻合。因此，PASS 实验的新应用是顺磁固体中 H 和潜在 N 的 NMR 实验武器库的极好补充。
