Sadoc Aymeric, Biswal Mamata, Body Monique, Legein Christophe, Boucher Florent, Massiot Dominique, Fayon Franck
Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France.
LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
Solid State Nucl Magn Reson. 2014 May-Jun;59-60:1-7. doi: 10.1016/j.ssnmr.2014.01.001. Epub 2014 Jan 22.
The relationship between the experimental (19)F isotropic chemical shift and the (19)F isotropic shielding calculated using the gauge including projector augmented-wave (GIPAW) method with PBE functional is investigated in the case of GaF3, InF3, TlF and several AlF3 polymorphs. It is shown that the linear correlation between experimental and DFT-PBE calculated values previously established on alkali, alkaline earth and rare earth of column 3 basic fluorides (Sadoc et al., Phys. Chem. Chem. Phys. 13 (2011) 18539-18550) remains valid in the case of column 13 metal fluorides, indicating that it allows predicting (19)F solid state NMR spectra of a broad range of crystalline fluorides with a relatively good accuracy. For the isostructural α-AlF3, GaF3 and InF3 phases, PBE-DFT geometry optimization leads to noticeably overbended M-F-M bond angles and underestimated (27)Al, (71)Ga and (115)In calculated quadrupolar coupling constants. For the studied compounds, whose structures are built of corner shared MF6 octahedra, it is shown that the electric field gradient (EFG) tensor at the cationic sites is not related to distortions of the octahedral units, in contrast to what previously observed for isolated AlF6 octahedra in fluoroaluminates.
在GaF3、InF3、TlF以及几种AlF3多晶型物的情况下，研究了实验测得的（19）F各向同性化学位移与使用包含投影增强波（GIPAW）方法并结合PBE泛函计算得到的（19）F各向同性屏蔽之间的关系。结果表明，先前在第3族碱金属、碱土金属和稀土元素的碱性氟化物中建立的实验值与DFT - PBE计算值之间的线性相关性在第13族金属氟化物的情况下仍然有效，这表明它能够以相对较高的准确度预测多种晶体氟化物的（19）F固态NMR谱。对于同构的α - AlF3、GaF3和InF3相，PBE - DFT几何优化导致M - F - M键角明显过度弯曲，并且（27）Al、（71）Ga和（115）In的计算四极耦合常数被低估。对于所研究的由角共享MF6八面体构成结构的化合物，结果表明阳离子位点处的电场梯度（EFG）张量与八面体单元的畸变无关，这与先前在氟铝酸盐中孤立的AlF6八面体中观察到的情况相反。
