INVESTIGATION OF THE ZERO-FIELD SPLITTING OF D(8) IONS IN PSEUDO-TETRAGONAL NI(II) COMPOUNDS

This paper presents a cluster approach to the zero-field splitting (ZF S) of the ground state (3)A(2)(F) of d(8) ions with tetragonal symmetr y, in which not only the spin-orbit coupling of the central transition -metal-ion but also that of ligands contributes. For some pseudo-tetra gonal Ni(II) compounds the calculated values of the ZFS parameter foll ow 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.