CRYSTAL-FIELD OF COMPLEX PARAMETERIZATION AND METAL-LIGAND DISTANCE DEPENDENCE OF THE PARAMETERS

A particular feature of the crystal field potentials of complex parame terization consists in possibility of elimination every one of their i maginary parameters ImB(q)k by means of suitable rotation of the coord inate system. Mutual positions of the coordinate systems corresponding to these compensation points are expressible in the frame of the supe rposition model. Accuracy of the determination in the light of experim ental data turns out to be better than that for any other parameter of the model. It allows one to verify correctness of the parameterizatio n schemes, and in the case of dispersion of metal-ligand distance to a nalyse the distance dependence of the crystal field parameters. The de pendence reflects the strength of interaction between the electronic s tates of the ion with lattice vibrations. The proposed method has been illustrated by a few examples of C2 and C(s) crystal fields in the ra re earth (3+) or uranium (4+) ion - fluoride ligand systems.