EPR-spectroscopy of disordered solids

The monography is devoted to the investigation of disordered solid structure by the EPR method. The general approach to investigations by the EPR method is based on the concept of distribution of spectroscopy parameters (parameters of the spinhamiltonian and angles assigned the orientation of paramagnetic centers). Analytical expressions of the EPR spectra of center systems with distributed spectroscopy parameters as well as calculational experiments point to the possibility of existence of singularities (narrow lines) at arbitrary high disordering. Extraction of structure information from the EPR spectra of disordered solids by the parametrization method is possible using approximation of experimental spectra computed. As a result, characteristics of distribution of spin-hamiltonian parameters conneted with the proper characteristics of distribution of the short-order parameters, are established. General laws of short-range order formation is monocrystalline solids: low local symmetry in average and high ordering, are detected taking oxide glasses alloyed with transition and rare-earth ions as an example. The degree of continuous violations of the short-range order in oxide glasses is 1-3% for interatomic distances and several degrees for structure angles. General tendency to conservation of the short-range order in noncrystalline state of the substance is confirmed by this fact. 450 refs.; 71 figs.; 15 tabs