Al NMR spectral parameters in metallic alloys*

Among the diverse range of existing alloys, Al-containing intermetallics are of great interest, mainly for structural, oxidation, corrosion, and sulfidation-resistant applications. Due to their diversified crystal chemistry, their atomic-level structural characterization is of great relevance, not only for the industry but also for basic research. In this context, ²⁷Al solid-state NMR experiments have been used for crystal structure validation and also pointed as valuable source of information regarding electronic structure. Nevertheless, the anisotropic nuclear interactions are quite complex in such systems, mainly due to the breaking of the spin-degeneracy of conduction electrons in the presence of an uniform external magnetic field. We report here the use of the GIPAW method for the computation of ²⁷Al NMR spectral parameters in nonmagnetic metallic solids, covering a wide range of isotropic chemical shifts (from about -200 to 1600 ppm). The results achieved demonstrate the possibility to expand the applications of this experimental technique with the aid of first-principles simulations, with deeper insight into nuclear interactions and less speculative assignments.