Theoretical interpretation of the temperature dependence of zero‐field splitting of Ni2+ in NiSiF6 · 6 H2O

Abstract

AbstractBy use of a trigonal crystal‐field model and by means of the eigenvalues and eigenvectors of a d8 (C) ion, a unified calculation is given for the spectral fine structure, the EPR parameters (D, 9|, 9⟂), and the EPR absorption condition (H,v) of Ni2+ ions in NiSiF6· 6H2O at different temperatures. The theoretical results agree well with the findings. It is shown that the trigonal field parameter v, which describes the splitting degree of the t2g orbitals in a trigonal field, has approximately a linear temperature dependence, v (cm−1) = 117.3 + 0.4898 T (K). This is shown to be the physical mechanism of the temperature dependence of the zero‐field splitting parameter D. The theoretically predicted EPR absorption conditions (H,v) and a very slight temperature dependence of the g‐values also agree very well with the findings.