Russian Journal of Physical Chemistry B最新文献

The work discusses heterophase accumulation reactions for sulfates and nitrates in the atmosphere and their part in aerosol haze formation. According to the atmosphere composition monitoring data on Beijing, it is high air humidity and high ammonia content that turn out to be crucial for involvement of chemical processes into haze formation in the atmosphere. With regard to this, generation of sulfates during the reaction SO_2(gas) (xrightarrow{{{text{Mn/Fe}}{text{, }}{{{text{O}}}_{{text{2}}}}}}{text{SO}}_{{{text{4(aer)}}}}^{{2 - }}) goes into the fast degenerate-branched mode which initiates formation of nitrates. Occurring simultaneously with regional transport, this is accompanied by hygroscopicity of particles and their mass concentration increasing at rates which are characteristic of haze formation.

The reactions of dehydrogenation of ethane to ethylene, propane to propylene, ethylbenzole to styrene, and cumene to α-methylstyrene on the surface of clusters of tungsten oxides have been studied using quantum chemical simulation. The calculation of sequential two-stage hydrogen adsorption on various active centers of clusters of tungsten oxides W₂O₃, WO₂, WO₃, modeling the studied nanoparticles WO_x, is carried out. According to the analysis of the data obtained, intermediates and products of adsorption complexes on the oxygen active centers of tungsten oxide clusters have greater energy stability, which suggests the occurrence of dehydrogenation reactions through the oxygen active centers of oxidized tungsten nanoparticles.

The rotational relaxation of H₂ (X¹∑_g, v = 1, J = 9) molecules during collisions with H₂ and N₂ was experimentally investigated. The rotational relaxation rate coefficient of H₂(1,9) molecules was determined by fitting the Stern–Volmer equation. At 297 K, the self-relaxation rate coefficient for H₂(1,9)–H₂ collisions in a pure H₂ system was (1.79 ± 0.04) × 10^–14 cm³ s^–1, while the rotational relaxation rate coefficients for H₂(1,9) molecules colliding with H₂ and N₂ in a H₂–N₂ mixture were (0.74 ± 0.09) × 10^–14 cm³ s ^–1 and (3.40 ± 0.21) × 10^–14 cm³ s^–1, respectively. The evolution profiles of the population distribution across various levels of H₂ (v = 1, J ≤ 9) were measured in H₂–N₂ mixtures, providing experimental evidence for the multi-quantum relaxation of H₂(1,9) molecules. Based on the analysis of the dynamic equations, it can be concluded that the primary pathway for multi-quantum relaxation of H₂ with ΔJ = 4 is via rotational-rotational collisions between H₂–H₂. The self-relaxation rate coefficient of H₂(1,9) molecules within a delay time of 2 μs was approximately 29% higher than that observed thereafter, indicating that rotational-rotational relaxation between H₂ molecules occurs more rapidly than rotational-vibrational relaxation involving both H₂ and N₂. In the temperature range of 297–410 K, increasing temperature significantly enhances the rotational-vibrational relaxation of H₂(1,9) with both H₂ and N₂, while the rotational-rotational collisions among H₂ molecules exhibit small dependence on temperature.

The density functional theory framework was employed in this research work to compute and describe the structural, electronic and optical properties of dilute bismide AlP_1–xBi_x alloys. The Wien2k code with the local density approximation was used for these computations. Furthermore, the modified Becke-Johnson exchange and correlation potentials were used to obtain an accurate band structure profile for AlP_1–xBi_x ternary alloy. Using Vegard’s law, we discover that a minor bending parameter (–0.19 Å) is revealed by the fluctuation of the lattice parameters vs. the composition x of Bi reveals a small bowing. However, these findings reveal a strong band gap decrease (0.240 eV/%Bi) with the increase in Bi content accompanied by an augmentation in the spin-orbit splitting energy Δ_so (0.156 eV/%Bi for x from 0 to 0.03125). Moreover, the band structure analysis proves that crossover points of (Γ–X) indirect to (Γ– Γ) direct gap energies occur at x = 0. (065). Ultimately, we calculated the variation of the optical characteristics of AlP_1–xBi_x compounds, such as dielectric function and refractive index versus Bi compositions. The determined optical properties have suggested that AlP_1–xBi_x alloy has higher optical efficiency since it has less energy loss than AlP. The study also revealed that the optoelectronic features of AlP_1–xBi_x alloy can be more precisely tailored by adjusting the Bi mole fractions in this alloy. These results highlight the potential of AlP_1–xBi_x alloys for advanced applications in optical devices, including laser diodes and detectors, particularly those operating in the near-Infrared spectrum.

In the fuel cell of a solid acid electrolyte, H⁺ conducting oxyanion salt (solid acid) consists of a solid supported within the membrane which is saturated with H₂O for any further ions transporting. In this study, Platinum-Iridium binary electrodes were prepared and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical techniques, and CO stripping. By this work we simulated our system to reduce the poisoning effect of mono oxide carbon (CO) problem, and an acceptable progress has already been made in improving the anode CO tolerance. We used Platinum-Iridium alloys to reduce the poisoning effect, which exhibited an alloy with Pt(30%)/Ir(70%) to be more tolerant to CO than pure Pt. By DFT method, we calculated the energetics of CO adsorbed on the system to be such that CO tends to diffuse from catalytically active Platinum onto the Iridium substrate. This mechanism requires Platinum-Iridium islands to be small. Meanwhile further DFT calculations exhibited the propensity of Platinum-Iridium atoms to coalesce and form with iridium. For any further confirmation of the results the cyclic voltammograms of a Platinum(111) electrode before and after deposition of various amounts of Platinum-Iridium alloys were also tested and finally hydrogen and water diffusion through h-BN located in two electrodes were discussed. As a result, it was confirmed that Iridium loading up to 70% was caused in electrochemically active surface (EAS) area and better electro-catalytic performance toward methanol electro-oxidation reaction.

In this study, the carmustine anticancer drug molecule and zigzag (8,0) single-walled carbon nanotube were optimized using density functional theory and the B3LYP method with a 6-31G basis set. The electronic properties before and after placing the carmustine drug molecule on the internal and external surfaces of the carbon nanotubes (8,0) were then studied and measured. The interaction of the carmustine molecule with the carbon nanotube (8,0) resulted in an increase in dipole moment and a decrease in gap energy, chemical hardness index, and stability in most of the studied nanostructures. This led to an increase in the electrical conductivity and quasi-metallic properties of these nanostructures.

The effect of cationic surfactant, cetyltrimethylammonium bromide (CTAB) and anionic surfactant, Sodium dodecyl sulfate (SDS) on the chromic acid oxidation of L–Leucine in perchloric acid medium at a constant ionic strength of 3.25 mol dm^–3 and at 35°С have been investigated spectrophotometrically. The reaction exhibits a 3 : 2 stoichiometry (Leucine: Quinoline Dichromate). The reaction shows first order dependence on oxidant Quinoline Dichromate, fractional first order on Leucine and Acid. The final products of oxidation of leucine were identified as the corresponding aldehyde Isopentaldehyde (3-methylbutyraldehyde), ammonium ion and carbon dioxide. The rate of reaction increased with the increase in dielectric constant of the medium. Both the surfactants, cetyltrimethylammonium bromide and Sodium dodecyl sulfate catalyze the reaction, however the effect of anionic surfactant is pronounced than cationic surfactant. Critical Micellar Concentration (CMC) of SDS and CTAB in aqueous solutions and amino aqueous solutions have been determined and thermodynamic parameters of micellization were also evaluated in both presence and absence of amino acid.

All-solid-state batteries (ASSBs) have come into focus in recent years as energy storage devices with energy densities potentially exceeding those of conventional lithium-ion batteries (LIBs). However, in practice, severe problems still must be solved. To reach high energy densities, it is indispensable to use lithium as anode and to build composite cathodes with high active material loading in the range of 85 wt %. In order to achieve fast ion transport inside the cathode despite the high active material loading, the solid electrolyte should have a high ionic conductivity and should form a continuous phase with low tortuosity ion transport pathways. By this research, we tested the conductivity amounts from various substrates containing amorphous glass, SSBM, and with glass-ceramic samples. Via SSBM technique, silicon nanoparticles were used as anode material, and it was exhibited the charge and discharge curves in the battery cell was cycled between 0.01 and 1.5 V versus Li⁺/Li at a current density of 220 mA g^–1 at room temperature. Since the high resistance, causes degradation of the interface between the cathode material (LiCoO₂) and the solid electrolyte, we added GeS₂ and SiS₂ to the Li₂S–P₂S₅ system for obtaining higher conductivities and better stability of the electrode/electrolyte interface.

In this work, adsorption of pyridine on the Mg₄O₄ cluster was examined at the LC-ωPBE/6-311G(d, p) level of theory. para-Substituent effect of pyridine ring was reported on the structural, energetic and thermodynamics parameters of the adsorption. Dependencies of computed parameters with Hammett’s constants of substituted were given. Also, isotopic effect of replacing of hydrogen atoms with deuterium atoms on the adsorption thermodynamics was illustrated. Charge decomposition analysis (CDA) computations revealed amount of charge transfer between to fragments.