International Journal of Quantum Chemistry最新文献

The strain can regulate the electronic properties of transition metal sulfides and enhance their application in ion battery electrode materials. In this article, the potential of single-layer SnS₂ as anode material for magnesium ion batteries under shear strain and torsional strain was studied by first-principles calculation. The calculation of adsorption energy shows that the strain does not have a great influence on the structural stability. The band gap of SnS₂ calculated by HSE06 is 2.210 eV. When Mg is on the surface of SnS₂, the band gap of SnS₂ drops to 0.113 eV, which shows quasi-metallic properties. Both strains can regulate the band gap value of SnS₂. The diffusion energy barrier of SnS₂ after strain is significantly lower than that without strain. After torsion strain, the diffusion barrier of Mg ions on SnS₂ is 0.11 eV. The research results provide a theoretical basis for the design of magnesium ion batteries.

Rare-earth ternary materials are distinguished by their tunable optoelectronic characteristics and high thermal stability. First principles computations examine the intricate interaction of novel rare-earth-based ternary chalcogenide's electronic, optical, and thermoelectric properties. The spin-down channel of PrHSe exhibits a substantial energy gap resulting in half-metallic behavior. The f orbitals of Pr and Er play an important role in forming bonds with Se and H atoms, contributing significantly to the valence band. The preponderance of Pr-f and Er-f orbitals near the top of the valence band indicate that electrons in these orbitals are the most energetic and participate in bonding interactions within these materials. The ErHSe has a greater absorption rate than PrHSe, and both materials behave isotropically in the xx and zz directions. The highest peaks of the reflection coefficient (50%–70%) in the 1.0–13.8 eV range suggested a significant level of UV reflectivity. The PrHSe has a higher intrinsic carrier concentration for conduction than ErHSe. At lower temperatures, carrier concentrations increase due to thermal activation processes, improving the Seebeck coefficient in these materials.

Utilizing the reactive molecular dynamics (ReaxFF MD) simulation, we conducted a comprehensive study on the impact of basicity (OH⁻/Al³⁺ ratio), concentration, and temperature on the hydrolysis and polymerization reactions of Al³⁺-solvated molecules. Through simulations, we analyzed the structural changes, energy fluctuations of the system, and the evolution patterns of reaction products under different parameters, which were subsequently validated by experimental data. The research results indicate that hydroxide ions in the solution directly influence the breakage of OH bonds in the coordinating water molecules of solvated aluminum ions. This, in turn, affects the number of H₂O and OH⁻ ions coordinated with Al³⁺, leading to changes in hydrolysis products. Additionally, the number of OH⁻ ions surrounding Al³⁺ affects the electrostatic repulsion, making it easier for polymerization reactions to occur as the system approaches the point of zero charge. On the other hand, an increase in concentration and temperature enhances the frequency of cluster collisions, thus contributing to an increase in polymerization degree. The experimental results align closely with our simulated predictions. As the pH value increases, the particle size exhibits a trend of first increasing and then decreasing, reaching a maximum at the point of zero charge. Simultaneously, an increase in concentration also prompts an increase in particle size. The combination of these empirical results with simulations enhances the credibility and reliability of our model's predictive capabilities. This study not only expands our understanding of the relevant chemical reaction processes but also provides important theoretical support for practical applications in related fields.

Spectrum-based topological indices (eigenvalue-based topological indices), a valuable tool for analyzing molecular structure. These topological indices are metrics that reflect the inherent characteristics of chemical substances, were employed in conjunction with quantitative structure-property relationship (QSPR) to investigate nonsteroidal anti-inflammatory drugs (NSAIDs) which are used toalleviate or eliminate pain sensations in affected areas. We have to use mathematica to compute various eigenvalue-based indices and utilized statistical software to identify correlations between these indices and key physical properties of NSAIDs. The analysis revealed that specific indices, including $��{�E�}_{�F�Z�S�}�$ index, $��{�\rho �}_{�F�Z�S�}�$ index, $��{�E�}_{�I�S�I�S�}�$ index, and $��{�E�}_{�A�B�C�S�}�$ index exhibited strong associations with properties like complexity and refractivity, boiling point, polarity, and molar weight, respectively.

The analysis of various chemical structures can be done by using topological indices (TI), graph polynomials, and other useful tools that graph theory offers. The mathematical entries called TI are subtracted from the chemical structure. In this article, we investigate the neighborhood degree based topological indices of $��T�U�{�C�}_{�4�}�{�C�}_{�8�}�\left(�R�\right)�$ nanotube via direct and NM-polynomial. The indices which we have computed are first, second, third, fourth, fifth NDe indices, third version of Zagreb index, neighborhood second Zagreb index, neighborhood second modified Zagreb index, neighborhood forgotten topological index, neighborhood general Randic index, neighborhood inverse sum index, fourth atom bond connectivity index, fifth geometric arithmetic index, fifth arithmetic geometric index, fifth hyper first and second Zagreb index.

This study explores the reaction mechanism between [(BDI)Ca(μ-H)]₂ and cyclopentadiene (C₅H₆). By analyzing the reaction pathways, it is found that compared with the traditional CaH/CC insertion reaction of polyenes with [(BDI)Ca(μ-H)]₂, C₅H₆ is more inclined to undergo a CaH/CH₂ dehydrogenation reaction, resulting in more stable cyclopentadienyl complexes. The subsequent reactions also tend to continue with dehydrogenation to form dimeric complexes. The aromatization process of C₅H₆ is a key factor driving this reaction trend. This result provides a new perspective for understanding the catalytic behavior of calcium hydride derivatives and can help in the design and synthesis of new catalysts and functional materials based on such compounds.

Based on irreducible representations of generalized quaternion groups, closed-form formulae of Kirchhoff indices and resistance distances between vertex pairs of Cayley graphs on these groups are given.

To understand the nature of heterogeneous catalytic processes and improve their efficiency, it is necessary to conduct both experimental and theoretical studies. At the same time, there is no unified approach to obtaining the necessary data using quantum chemistry methods. In this work, problems of the existing calculational approaches are analyzed. The obtained information is used to develop the original three-layer embedded cluster model approach, which is shown to be the most effective. The general algorithm for obtaining such models for various oxides is formulated. The sufficient accuracy of the proposed models in predicting geometric and energy characteristics, vibrational frequencies, activation barriers, and thermodynamic characteristics is verified. The specifics of calculating the thermodynamic characteristics of heterogeneous processes using the proposed cluster models is studied in detail. The developed approach is an effective tool for studying the mechanism of heterogeneous catalytic processes both by itself and in combination with experiment.