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Sadoc, A., Body, M., Legein, C., Biswal, M., Fayon, F., Rocquefelte, X. & Boucher, F. (2011) NMR parameters in alkali, alkaline earth and rare earth fluorides from first principle calculations. Phys. Chem. Chem. Phys. 13 18539–18550.
Added by: Laurent Cournède (2016-03-10 21:32:21) |
| Type de référence: Article DOI: 10.1039/c1cp21253b Numéro d'identification (ISBN etc.): 1463-9076 Clé BibTeX: Sadoc2011 Voir tous les détails bibliographiques  |
Catégories: ST2E Mots-clés: ab-initio calculations, angle-spinning nmr, cross-polarization nmr, density-functional theory, electric-field gradients, isotropic chemical-shifts, nuclear-magnetic-resonance, projector-augmented-wave, resolution f-19 mas, solid-state NMR Créateurs: Biswal, Body, Boucher, Fayon, Legein, Rocquefelte, Sadoc Collection: Phys. Chem. Chem. Phys. |
Consultations : 1/540
Indice de consultation : 4% Indice de popularité : 1% |
| Résumé |
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F-19 isotropic chemical shifts for alkali, alkaline earth and rare earth of column 3 basic fluorides are measured and the corresponding isotropic chemical shieldings are calculated using the GIPAW method. When using the PBE exchange-correlation functional for the treatment of the cationic localized empty orbitals of Ca2+, Sc3+ (3d) and La3+ (4f), a correction is needed to accurately calculate F-19 chemical shieldings. We show that the correlation between experimental isotropic chemical shifts and calculated isotropic chemical shieldings established for the studied compounds allows us to predict F-19 NMR spectra of crystalline compounds with a relatively good accuracy. In addition, we experimentally determine the quadrupolar parameters of Mg-25 in MgF2 and calculate the electric field gradients of Mg-25 in MgF2 and La-139 in LaF3 using both PAW and LAPW methods. The orientation of the EFG components in the crystallographic frame, provided by DFT calculations, is analysed in terms of electron densities. It is shown that consideration of the quadrupolar charge deformation is essential for the analysis of slightly distorted environments or highly irregular polyhedra.
Added by: Laurent Cournède |