Effect of temperature on the local angular thermal expansion and local structure for nickel-doped zinc fluosilicate

A theoretical method for studying the local properties about Ni2+ ion in a trigonal ligand-field has been proposed by diagonalizing the complete energy matrix and considering the electron paramagnetic resonance (EPR) parameters D and g. For nickel-doped ZnSiF6 · 6H2O and ZnSiF6 · 6D2O systems, the local lattice distortion and local angular thermal expansion coefficient have been investigated at various temperatures. The calculated results indicate that the local structure around octahedral Ni2+ centre has a compression distortion in the two systems. Moreover, the temperature dependence of the local angular thermal expansion coefficient has also been analysed.