Zero-field splitting parameters of Gd³⁺ ions localized in three types of tetrahedral clusters were estimated using the superposition approximation. The cluster structures were determined from the minimum condition of the energy of a lattice with a rare earth cluster. The monoclinic centers with b₂₀ = -345 MHz and b₂₀ = -600 MHz were related to [CdY₂GdF₂₆] and [Cd₂YGdF₂₆] clusters, respectively.

The investigations of Ag-contaning tennantite, belonging to the group of tetrahedrite-based sulfides, were performed by means of copper nuclear quadrupole resonance (NQR) in a temperature range from 4.2 K up to 60 K. These experiments showed that copper nuclear spin-lattice relaxation rate T₁^-1 and nuclear spin-echo decay rate T₂^-1 depend on temperature in the same way as earlier studied samples with other impurity compositions. The obtained data are interpreted from the viewpoint of internal motions in the structure of tennantite. The analysis of copper NQR data at low temperatures points to magnetic phase transition near 60 K from paramagnetic phase to the phase, which resembles spin-glass-like constitution.

The asphaltene powders have been studied by ¹H NMR relaxation method, differential scanning calorimetry (DSC) and X-ray structure analysis. The asphaltene samples were extracted from three oils with different component and hydrocarbon-group compositions. It was found that free induction decays (FID) of various asphaltene samples contain Gaussian component with spin-spin relaxation times T₂ about 10?20 μs, which was named a solid component. The detecting possibilities of equilibrium first-order phase transitions and non-equilibrium glass-transitions on temperature dependence of part P_s of solid component in the ¹H NMR signal are presented. The ¹H NMR relaxation and DSC methods to study temperature properties of asphaltenes are compared. The glass-transition temperatures of side aliphatic chains of asphaltene molecules are measured. We set up that crystallization of high-molecular side aliphatic chains of asphaltene molecules is possible.

The new application of non-linear approximation for spectrum processing and multiplatform software for spectrum analysis with friendly user interface is suggested. Experimental spectrum is approximated by a sum of a number of functions. Each function can be approximated on selected interval separately when other functions are subtracted from experimental spectrum. All actions can be made using graphical user interface.

Temperature dependences of ferromagnetic resonance spectra of nanoparticles of magnetite dispersed in polyethylene glycol films and nickel in vaseline oil have been studied. Sharp changes in spectra position (g-value) and linewidth have been found for both systems in the temperature interval 60 - 100 K above glass transition point. These effects have not been observed for polyethylene glycol films prepared under external magnetic field. It has been shown that the effects observed are connected with formation of anisotropic aggregates from nanoparticles under magnetic field action. The main factors determining the temperature of spectra parameters changes are the matrix viscosity, particles translational mobility and spectrum sweeping time.

X-band ESR of chemically dehydrofluorinated poly(vinylidene fluoride) films has been studied in the 150 ? 375 K temperature range. Dehydrofluorinated films reveal an ESR signal with g-factor close to that of the free electron. The ESR parameters (integral intensity, width, g-factor) of the samples depend on duration of the chemical reaction, storage conditions and temperature. Heating above 375 K modifies paramagnetic component of the samples stored in air irreversibly, probably, as a result of hydrogenous radicals desorption and/or removal of oxygen, hydroxyl groups and moisture from the samples on heating. The deviation from the Curie law has been revealed for all the investigated samples.

Nuclear magnetic resonance (NMR), Raman spectroscopy and thermogravimetric methods were used to study the peculiarities of lithium ion replacement by protons in lithium metallates Li₂MO₃ (M=Ti, Zr). In this article we show that almost all protons in the final substitution products H₂MO₃ enter into the crystal structure. All protons in zirconium hydroxide belong to hydrogen-bonded OH-groups. Contrary, titanium hydroxide contains both hydrogen-bonded and isolated OH-groups. Protons in H₂ZrO₃ form hydrogen bonds weaker than in H₂TiO₃.