C. Basu

Effect of configuration interaction on crystal field splitting of Cu2+ ion

Abstract The effect of excited configurations 3 d 8 4 p , 3 d 8 4 d and 3 d 8 4 f on the crystal field levels Γ 3 and Γ 5 of tetrahedral and octahedral Cu 2+ ion via crystal field interaction has been discussed. The shift of the Γ 3 and Γ 5 levels due to configuration interaction has been estimated in the two cases within the framework of crystal field model carrying out the perturbation calculation upto the second order and using Slater functions for the radial integrals.

Effect of Configuration Interaction on Crystal Field Splitting of Fe2+ Ion

The effect of excited configurations 3d54p, 3d54d, and 3d54f on the crystal field levels Γ3 and Γ5 of tetrahedral and octahedral Fe2+ ion via crystal field interaction has been discussed. The shift of the Γ3 and Γ5 levels due to configuration interaction has been estimated in the two cases within the framework of crystal field model carrying out the perturbation calculation up to second order and using Slater functions for the radial integrals. Such calculation shows that in the case of tetrahedral Fe2+ ion in ZnS, the net effect of the excited configurations 3d54p, 3d54d, and 3d54f on the crystal field spectra is to close up the levels Γ5 and Γ3 by an appreciable amount of about 1000 cm−1 and the major part of the contribution comes from 3d54p. In the octahedral case also (Fe2+ in MgO), the effect arising from 3d44d only is not negligible although comparatively smaller, the separation (Γ3−Γ5) is narrowed by about 380 cm−1.

Effect of crystal field on the spin density at the copper nucleus in copper complexes

The role of lower symmetry component of the crystal field in causing a mixing of excited 3dx−1 4s with the ground 3dx configuration and leading to spin density at the nucleus for iron group ions was suggested by Griffith and Orgel. This mechanism has been examined in detail for the two low-symmetry copper complexes, one square planar (D4h symmetry) and the other distorted tetrahedron (D2d symmetry) and the calculation has been performed using the powerful Racah method and tensor operator technique. It is found that for the two types of copper complexes, copper pthalocyanin (square planar, D4h symmetry) and cesium copper chloride (distorted tetrahedron, D2d symmetry) the contribution from this mechanism to the spin density at the nucleus vanishes identically.