Lukin S. Static and dynamic deformations of paramagnetic centre in EPR spectra of iron group ions

The thesis is devoted to an experimental research of influence uniform and axial compression of a researched sample on EPR spectra of iron group ions. The circle of the investigated objects includes paramagnetic centers octahedral and tetrahedral co-ordination with tetragonal and trigonal distortions. The existence of natural link of parameters spin Hamiltonian with deformations of a correct polyhedron of the nearest environment of a magnetic ion is installed. The complex researches of EPR spectra of Jahn-Teller centers of ions in 2Е state (Cu2+) in trigonal crystals, including learning of temperature and frequent dependencies of EPR spectrum, research of influence for him uniform and axial compression of a researched sample are carried out. On the basis of the carried out experiments the principal characteristics of investigated Jahn-Teller system: Jahn-Teller energy; the linear vibronic interaction constant; deformation coefficient; the value of a barrier high between absolute minima of adiabatic po tential are obtained. Are detected and the features of spectra EPR, obliged to manifestation of dynamics of a nuclear core are interpreted. The switching, induced by pressure, of a direction of an axis of Jahn-Teller distortion in (ND4)2Cu(SO4)2Ч6D2O and, accompanying this switching, hysteresis of change of parameters of a EPR spectrum is investigated.