Effects of Li Confined Motion on NMR Quadrupolar Interactions: A Combined 7 Li NMR and DFT-MD Study of LiR 2 (PO 4 ) 3 (R=Ti or Zr) Phases.

Autor: Diez-Gómez V; Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain., de Andres PL; Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain., Sanz J; Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain.
Jazyk: angličtina
Zdroj: ChemSusChem [ChemSusChem] 2020 Mar 09; Vol. 13 (5), pp. 1027-1036. Date of Electronic Publication: 2020 Jan 30.
DOI: 10.1002/cssc.201902991
Abstrakt: Ab initio molecular dynamics (MD) simulations and NMR GIPAW (gauge including projector augmented wave) calculations have been used to analyze the coordination and mobility of Li ions in LiTi 2 (PO 4 ) 3 (rhombohedral), LiZr 2 (PO 4 ) 3 (triclinic), and LiZr 2 (PO 4 ) 3 (rhombohedral) phases. Significant discrepancies are observed between static calculations of 7 Li quadrupolar parameters and experimental values. The dynamical origin of this disagreement is demonstrated by incorporating in the calculations thermal vibrations and local motion of atoms with MD simulations. For LiTi 2 (PO 4 ) 3 , the quadrupolar constant associated with Li ions grows with temperature because the local symmetry of the system decreases, whereas for the Zr phases, the quadrupolar constant decreases because thermal vibrations reduce the anisotropy of the interaction. Finally, for both Zr phases, MD yields Li distributions that compare well with disorder reported from diffraction studies.
(© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)
Databáze: MEDLINE
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