Zhitlukhina O. The spin-state evolution of 3d ions in complexes of different symmetry

The thesis is devoted to a study of the evolution of spin states of 3d metals in complexes of different nature and symmetry, due to different kinds of complex distortions. A new parameterization of the crystal field theory has been applied for the calculations. A scheme for constructing spin-state diagrams representing the surface mean square to-tal spin of metal ions on the plane parameters "effective nuclear charge of a metal ion - distortion of the coordination complex" or in the plane of two types of distortion at a given value of the effective charge has been proposed. It allowed to study the evolution of spin states under the influence of external fields and pressures, as well as in the pres-ence of random distortions surrounding the metal ion, which takes place in real crystals. The selected calculation methodology made it possible to interpret adequately spectra of the electron paramagnetic resonance of a chromium ions in the compound Hg1-xCrxSe and a copper ion in a normal spinel ZnAl2O4. The dependence between the structure of ESR spectra of chromium ions in the compound Hg1-xCrxSe and trigonal distortions of the local environment of a chromium ion has been revealed. The relationship between the degree of trigonal distortions of an oxygen octahedra in spinel ZnAl2O4 containing a bivalent copper ion, and a minimum depth of adiabatic potential was established for the first time.