Vol 58, No 3 (2024)

The energy and spin parameters of poly(3-alkylthiophene) oligomers and their composites with aromatic hydrocarbons are calculated. The coexistence of polarons with different degrees of delocalization in the studied compounds has been identified. Periodic changes in the electronic and spin properties of composites were detected, initiated by the interaction of oligomers with aromatic nanoadditives. The anisotropic parameters of the spin Hamiltonians of the studied systems are obtained and their high-resolution EPR spectra are calculated.

The possibility of using a number of methacrylate-containing N,N-diethyl-4-(phenyldiazenyl)anilines with various para-substituents with respect to the azo group (-H, -Br, -NO₂) as photoinitiators of radical polymerization is considered. The electrochemical and photoluminescent properties of these compounds have been studied. In the presence of azo dyes, two-photon photopolymerization of pentaerythritol triacrylate was carried out by focused radiation from a femtosecond laser with a wavelength of 780 nm. Structures with minimum linear element sizes of 94 ± 5 nm were obtained by DLW nanolithography, as well as 3D microstructures of complex architecture.

Two-photon absorption cross sections of aqueous solutions of the styryl dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) and its inclusion complexes with cucurbit[n]urils (CB[n] n = 6–8) were measured using fluorescence spectroscopy. A nonmonotonic dependence of the cross-section size on the excitation wavelength and on the cavitand cavity size was found. Compared with a free dye, a sevenfold increase in the two-photon absorption cross section was observed in DASPI inclusion complexes with CB[8] at an excitation wavelength of 980 nm.

The influence of acceptors of the water radiolysis primary products of the H atom and e_a^–_q on the spectra and intensity of the Tb³⁺ ion radioluminescence and photoluminescence in aqueous solutions of TbCl₃ and Tb(NO₃)₃ is considered. The activation effect of Tb³⁺ radioluminescence in the presence of H acceptors was revealed, indicating the presence of a specific quenching reaction (Tb³⁺)* by this radiolysis product, inhibited by its acceptors. An increase in activation was found in the joint presence of H and hydrated electron acceptors in the solution; for acceptors of the latter, a similar activation effect of Tb³⁺ radioluminescence was established earlier.

For the first time, nanostructured thin films of the β-Ga₂O₃−GaN system were obtained by plasma chemical deposition from the gas phase (PECVD) on c-sapphire substrates. High-purity metallic gallium, as well as high-purity gaseous nitrogen and oxygen were used as sources of macro components. The low-temperature nonequilibrium plasma of an inductively coupled HF (40.68 MHz) discharge at a reduced pressure (0.01 Torr) was the initiator of chemical transformations between the starting substances. A mixture of oxygen and nitrogen was used as a plasma-forming gas. The plasma chemical process was studied using the optical emission spectroscopy (OES) method. The obtained thin films of the β-Ga₂O₃−GaN system with a GaN phase content of 2 to 7% were characterized by various analytical methods.

This work is devoted to the numerical modeling of the reaction of methane conversion to acetylene under plasma-jet pyrolysis conditions and a comparison of the obtained results with the available experimental data. The calculations were performed within the framework of the ideal plug-flow reactor model for atmospheric pressure. The analysis of the main processes of methane decomposition and acetylene formation was carried out in cases where either hydrogen or methane was used as a plasma-forming gas. The results of calculations of the main products of methane decomposition (hydrogen and acetylene) agree quite well with the experimental data.