Investigation of the Zero-Field Splitting of d8 Ions in Pseudo-tetragonal Ni(II) Compounds

Abstract This paper presents a cluster approach to the zero-field splitting (ZFS) of the ground state 3A2(F) of d8 ions with tetragonal symmetry, in which not only the spin-orbit coupling of the central transition-metal-ion but also that of ligands contributes. For some pseudo-tetragonal Ni(II) com pounds the calculated values of the ZFS parameter follow the order Cl-> Br-> I-. This agrees with the experimental finding, while the pure crystal field approach considering only the coupling of central metal ion yields the opposite trend.