ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 34, Number 1
JKCSEZ 34(1)
February 20, 1990 

An effect of the spin-orbit coupling interaction of ligand orbitals and the intermixing │3d 〉and│4p > transition metal atomic orbitals on the ground state for a 3d9 system in a strong crystal field of tetragonally distorted tetrahedral symmetry that belongs to the D2d point group has been investigated in this work, applying the degenerate perturbation theory. An LCAO-MO analysis in terms of the known energies of the d-d transitions for the tetragonally distorted CuCl42- ion in a single crystal of Cs2CuCl4 shows that the covalent mixing of Cu 3d and ligand Cl 3p orbitals decreases dramatically with increasing Cu 4p contribution. The extent of effect on the energy level splitting for the ground state by the spin-orbit coupling interaction of ligand orbitals decreases significantly in order Γ7(E) → Γ6(E) > Γ7(B2) → Γ6(E) > Γ7(B2) → Γ7(E).