Silly G, Legein C, Buzaré J Y, Calvayrac F
Laboratoire de Physique de l'Etat Condensé, UMR. CNRS no. 6087, Université du Maine, Avenue Olivier Messiaen, Le Mans 72085, 9, France.
Solid State Nucl Magn Reson. 2004 Jun;25(4):241-51. doi: 10.1016/j.ssnmr.2003.09.001.
Electric field gradients (EFG) of 23Na and 27Al in three model fluoride crystalline powders AlF3, Na3AlF6 and Na5Al3F14 were computed using the density functional based electronic structure code WIEN97 and compared to values derived from nuclear magnetic resonance (NMR). First, results of measurements of 23Na and 27Al quadrupolar parameters in AlF3, Na3AlF6 and Na5Al3F14 were revisited by using high-resolution solid-state NMR. To determine chemical shifts and quadrupolar parameters with a high precision, the experimental procedure involved magic angle spinning, satellite transition spectroscopy and multi-quanta techniques applied to the quadrupolar nuclei together with a computed reconstruction of the NMR spectra. The large discrepancies which appear between previously published results in some cases, justify the use of ab initio calculations of the corresponding EFG using the WIEN97 code based on the known structural data of the crystalline phases. The agreement obtained between these calculations and the experimental results which is better than 10% in almost all cases supports the reliability of the present NMR investigations and of the crystallographic data.
使用基于密度泛函的电子结构代码WIEN97计算了三种模型氟化物晶体粉末AlF₃、Na₃AlF₆和Na₅Al₃F₁₄中²³Na和²⁷Al的电场梯度（EFG），并与核磁共振（NMR）得出的值进行了比较。首先，通过使用高分辨率固态NMR重新审视了AlF₃、Na₃AlF₆和Na₅Al₃F₁₄中²³Na和²⁷Al四极参数的测量结果。为了高精度地确定化学位移和四极参数，实验过程涉及魔角旋转、卫星跃迁光谱学和应用于四极核的多量子技术，以及NMR光谱的计算重建。在某些情况下，先前发表的结果之间出现的巨大差异证明了使用基于结晶相已知结构数据的WIEN97代码对相应EFG进行从头算的合理性。在几乎所有情况下，这些计算与实验结果之间获得的一致性优于10%，这支持了当前NMR研究和晶体学数据的可靠性。
