Electric field gradient calculations for LixTiS2 and comparison with 7Li NMR results

摘要: The elements of the electric field gradient tensor at Li position in intercalation compound ${\mathrm{Li}}_{x}\mathrm{Ti}{\mathrm{S}}_{2}$ (with $x=0.25$, 0.33, 0.67, and 1.0) were calculated with first-principles methods periodic supercell models. theoretical results obtained density functional Hartree-Fock hybrid compared experimental gradients extracted from $^{7}\mathrm{Li}$ NMR spectra literature our measurements presented here. dependence on basis set explicit form exchange-correlation was investigated. In agreement earlier studies a pronounced effect polarization functions site observed. After optimization internal degrees freedom $\mathrm{Li}\mathrm{Ti}{\mathrm{S}}_{2}$ all under consideration give quadrupole coupling constants close experiment. For $xl1$ found to depend more sensitively method which attributed differences description spin localization. calculations allow one distinguish between atoms placed octahedral tetrahedral interstitial sites host lattice $\mathrm{Ti}{\mathrm{S}}_{2}$.