The acid silicious sols obtained from synthetic silicates were investigated in this work. Using NMR microimaging it was found out the formation of considerable inhomogeneities in optically limpid samples at different stages of gel formation. They were interpreted as silicic acid polycondensation fronts. It was observed the character of spreading and fine structure of the fronts. By means of NMR relaxometry were discovered the some interesting effects at the relaxation dependences in time intervals, corresponding to gel formation transitional stages.

We report the first experimental observation of the photoinduced EPR spectra in KTa_1-xNb_xO₃ crystals (x = 0.012). The signal has two components: nearly isotropic with g_eff = 2 and strongly anisotropic one. Isotropic signal originates most probably from single localized photo-carriers - electrons or holes. Anisotropic spectrum is observed below 10 K and reveals a set of characteristic properties. It originates from the axial centers with axes coinciding with the C₄ axes of the crystal. Effective g-factor values are g_parallel = 2.106(3) and g_normal < 0.8. Angle dependencies of the intensity and the width of the anisotropic signal as well as the resonance field can qualitatively be explained within the simple J = 1 model. The observed anisotropic photoinduced EPR spectrum is tentatively assigned to excitons or bipolarons.

Quantum confinement of the shallow-donor electron wave function in ZnO nanoparticles is used to study nanocrystal samples by means of High-Frequency EPR. A method for deriving nanoparticle size distribution in the sample from the EPR line shape of the shallow donor is developed based on dependence of the shallow donor g-factor on nanoparticle size.