Zero Field Splittings of t23 Cubic Terms

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.