Vol 43, No 12 (2024)

The of adenine (Ade, C₅H₅N₅) and cyclodiglycine (DKP, C₄H₆N₂O₂) ions fragmentation formed in the singly electron capture during the interaction of molecules in the gas phase with C²⁺ and O²⁺ ions with an energy of 12 keV have been studied. The experimentally observed dependence of the relative fragmentation cross section of molecular ions on the type of projectile is qualitatively explained within the framework of the quasi-molecular model. Using the multi-configuration method of self-consistent field in complete active space (CASSCF), calculations of the fragmentation reaction paths of Ade⁺ and DKP⁺ ions were performed. The calculated appearance energies are in good agreement with the available experimental data.

Stepwise fourfold addition reactions of vinyl chloride type of allyl chloride growth radicals to fullerene C₆₀ leading to formation of adduct’s almost all possible types have been considered. The reactions product structures have been analyzed and the thermal characteristics, such as thermal effects and enthalpies of activation, have been calculated. At the radical-initiated interaction of allyl chloride and fullerene C₆₀, up to three allyl chloride growth radicals’ addition is possible. In this case, the trisadducts are stable allyl type radicals, which can attach a fourth allyl chloride radical to form molecular products.

For a countercurrent liquid–liquid plug reactor, theoretical studies of the implementation of possible types of stationary states were carried out. States such as a stable node and focus, and an unstable focus with a stable limit cycle (oscillations) have been discovered. Using these data, the evolution of stationary states with continuous changes in external control parameters was studied. When the relationship between the flow rates of the phases changes, a structure of stationary states is discovered, which can be realized both at the entrance and exit of the dispersion medium.

The aim of this study is to consider a photogeneration of charge carriers in nano-structured blends of the donor (D) and acceptor (A) materials. Upon optical excitation photons absorbed in one of these materials produce intramolecular excitons which can diffuse to the D–A interface and form at the interface the interfacial CT states. The interfacial CT state dissociates into a geminate pair of the non-equilibrium mobile electron and hole. In the present study, an empirical model describing thermalization of the non-equilibrium charges within the Coulomb well is proposed. Efficiency of the interfacial CT state dissociation into a pair of free charges is found as a function of the electric field applied, effective temperature and diffusion length of non-equilibrium electron-hole pairs.

In this work, using coarse-grained molecular modeling methods, the interactions of DNA-binding protein from starved cells (Dps) of the bacterium Escherichia coli with DNA sections of various lengths and composition were investigated. The binding features in two-dimensional crystals of the Dps protein were studied. Using free energy search methods – thermodynamic integration and linear interaction energy – the most favorable conditions for the binding of DNA and Dps were determined.

Nanocomposites based on graphite oxide airgel and superparamagnetic iron oxide nanoparticles (rGO ⋅ Fe₃O₄) are able to sorb potassium dichromate from aqueous solutions. The superparamagnetic nature of the composite makes it possible to extract it after the completion of the sorption process from the pollutant solution using an external magnetic field. The dependence of the degree of sorption of potassium dichromate by aerogels of the composition rGO ⋅ Fe₃O₄ on the mass of the sorbent, acidity, and temperature of the medium was studied. It has been shown that in order to increase the degree of potassium dichromate sorption by the rGO ⋅ Fe₃O₄ magnetic airgel, the process is best carried out at room temperature in media with low pH values. The results obtained make it possible to propose airgels based on graphite oxide and rGO ⋅ Fe₃O₄ iron oxide nanoparticles as environmentally friendly sorbents for water purification from the carcinogenic substance potassium dichromate. The proposed materials after the end of the sorption process can be completely removed from the reaction medium using an external magnetic field, thereby preventing their action as pollutants. It is important to note that the described 3D structures based on graphite oxide and nanoparticles of superparamagnetic iron oxide Fe₃O₄ are of practical importance for the treatment of wastewater from enterprises using an oxidative method for removing phenols, cresols, and cyan-containing substances from impurities using potassium dichromate and sulfuric acid.

The influence of cobalt additives on the phase composition, structural parameters, and morphology of indium oxide containing a mixture of crystalline phases has been studied. The hydrothermal synthesis method was used to obtain the corresponding systems. It has been shown that during the hydrothermal reaction, a mixture of phases of indium hydroxide and oxihydroxide is formed, which, in turn, after thermal decomposition, transform into cubic and rhombohedral indium oxide, respectively. Depending on the concentration of the introduced cobalt, the ratio between the phases changes. At a concentration of 0.05 at.% Co, the cubic phase prevails, while at an introduction of 0.25 at.% the rhombohedral compared to the undoped sample. An increase in the concentration of cobalt leads to a decrease in the particle size, as well as an increase in the specific surface area and porosity of the composites. At the same time, the introduction of cobalt does not significantly affect the morphology of the resulting systems.