NMR parameters in alkali, alkaline earth and rare earth fluorides from first principle calculations.

نویسندگان

  • Aymeric Sadoc
  • Monique Body
  • Christophe Legein
  • Mamata Biswal
  • Franck Fayon
  • Xavier Rocquefelte
  • Florent Boucher
چکیده

(19)F 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 Ca(2+), Sc(3+) (3d) and La(3+) (4f), a correction is needed to accurately calculate (19)F 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 (19)F NMR spectra of crystalline compounds with a relatively good accuracy. In addition, we experimentally determine the quadrupolar parameters of (25)Mg in MgF(2) and calculate the electric field gradients of (25)Mg in MgF(2) and (139)La in LaF(3) 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.

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عنوان ژورنال:
  • Physical chemistry chemical physics : PCCP

دوره 13 41  شماره 

صفحات  -

تاریخ انتشار 2011