Abstract

We have investigated the possibility of obtaining good approximate analytical expressions for the zero field splittings of cubic terms belonging to the t23 configuration. Spin—orbit, and trigonal and tetragonal field perturbations are considered, and a perturbation expansion based on a strong cubic field zeroth-order Hamiltonian is used. Only in the case of 4A2 and a2E terms does the expansion converge sufficiently rapidly for a single order of perturbation theory to provide a useful approximation for octahedral Cr3+ or tetrahedral Co2+ complexes. In the case of trigonal symmetry, we investigate the range of validity of the perturbation expressions, by comparison with exact numerical solutions of the crystal-field eigenvalue problem for the complete d3 configuration.