Carvalho José P, Jaworski Aleksander, Brady Michael J, Pell Andrew J
Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
Materials Department, Department of Chemistry and Biochemistry, Materials Research Laboratory, UC Santa Barbara, Santa Barbara, California, USA.
Magn Reson Chem. 2020 Nov;58(11):1055-1070. doi: 10.1002/mrc.5004. Epub 2020 Mar 6.
A new approach for processing satellite-transition magic-angle spinning (STMAS) and multiple-quantum magic-angle spinning (MQMAS) data, based on the two-dimensional one-pulse (TOP) method, which separates the second-rank quadrupolar anisotropy and paramagnetic shift interactions via a double shearing transformation, is described. This method is particularly relevant in paramagnetic systems, where substantial inhomogeneous broadening may broaden the lineshapes. Furthermore, it possesses an advantage over the conventional processing of MQMAS and STMAS spectra because it overcomes the limitation on the spectral width in the indirect dimension imposed by rotor synchronization of the sampling interval. This method was applied experimentally to the Al solid-state nuclear magnetic resonance of a series of yttrium aluminum garnets (YAGs) doped with different lanthanide ions, from which the quadrupolar parameters of paramagnetically shifted and bulk unshifted sites were extracted. These parameters were then compared with density functional theory calculations, which permitted a better understanding of the local structure of Ln substituent ions in the YAG lattice.
本文描述了一种基于二维单脉冲（TOP）方法处理卫星跃迁魔角旋转（STMAS）和多量子魔角旋转（MQMAS）数据的新方法，该方法通过双剪切变换分离二阶四极各向异性和顺磁位移相互作用。这种方法在顺磁体系中尤为重要，因为大量的非均匀展宽可能会使线形变宽。此外，它比传统的MQMAS和STMAS谱处理方法更具优势，因为它克服了采样间隔转子同步对间接维度谱宽的限制。该方法通过实验应用于一系列掺杂不同镧系离子的钇铝石榴石（YAG）的铝固态核磁共振，从中提取了顺磁位移和整体未位移位点的四极参数。然后将这些参数与密度泛函理论计算结果进行比较，从而更好地理解YAG晶格中Ln取代离子的局部结构。
