27Al NMR experiments and quadrupolar parameter ab initio calculations: Crystallographic structure refinement of β-Ba3AlF9

27Al quadrupolar parameters are determined for the three aluminium sites in β-Ba3AlF9 from the reconstruction of experimental SATRAS and MQ-MAS NMR spectra. These quadrupolar parameters are then computed using the DFT linearized augmented plane wave method implemented in the WIEN2k code. agreement between experimental and calculated values is obtained only after optimizing the β-Ba3AlF9 structure. The optimized structure is more satisfactory than the previously published one from a crystallographic point of view (bond lengths and angles). pproach which allows to refine crystallographic structures especially when they lack accuracy may be extendable to other compounds containing quadrupolar nuclei.