International Journal of Quantum Chemistry最新文献

The aggregation of Li₂MnO₃-like domains in Li-rich layered oxides (LLOs) causes severe capacity/voltage fading, which seriously impedes their commercial applications. Here, we design Co-free Li-rich LiFeNiMnO system with dispersed small-sized Li₂MnO₃–like domains (D-LFNMO) and aggregated Li₂MnO₃-like domains (A-LFNMO) to investigate effects of Li₂MnO₃-like domain sizes and Fe content on structures and oxidation process using density function theory (DFT) calculations. De-lithiation structures, structural stability and oxidization mechanism of lattice oxygen ions are explored. Structural stability is finished through calculating oxygen release energies and migration energy barriers of Mn⁴⁺ ions based on a climbing image nudged elastic band (CI–NEB) method. Research shows that LLOs with dispersed small-sized Li₂MnO₃-like domains and the moderate Fe content would possess highly reversible oxygen redox and excellent structural stability and would exhibit superior cycling stability of high capacity. The findings provide new perspectives and concepts for designing high-energy Li-rich cathodes.

The structural stability, elastic, optoelectronic, and thermoelectric characteristics of anti-perovskites Na₃XO (X = Cu, Ag) have been studied using density functional theory (DFT). The computed formation energy suggests these materials' potential synthesis and thermal stability. The structural and elastic properties of Na₃CuO and Na₃AgO anti-perovskite compounds were analyzed using the Perdew–Burke–Ernzerhof (GGA-PBE) generalized gradient potential approximation. The electronic and thermoelectric properties are calculated using the TB-mBJ approximation. The materials are identified as direct narrow band gap semiconductors with band gaps of 0.65 and 0.43 eV. The analysis of two-dimensional charge density contours indicates that Na₃CuO and Na₃AgO have a mixed bonding character, as validated by the investigation of electron charge density. We analyzed the optical properties of Na₃CuO and Na₃AgO, including dielectric function, refractive index, absorbance, optical reflectivity, and energy loss, using photon energy up to 6 eV. The investigated thermoelectric characteristics demonstrate figure of merit (ZT) values of 0.58 and 0.56 at room temperature. Consequently, the analyzed anti-perovskites might address waste heat management requirements and sustainable energy solutions.

This study shows the exploration of the gas-sensing capabilities of C₆N₈ material against toxic gases like phosphine (PH₃) and phosphorous trichloride (PCl₃). First-principles study based on M05-2X/LanL2DZ (d, p) method was performed to investigate the interaction energy (E_int.), frontier molecular orbitals (FMOs), natural bonding orbital (NBO), noncovalent interactions (NCIs), partial density of states (PDOS), molecular electrostatic potential (MEP), and quantum theory of atoms in molecules (QTAIM) analyses. The interaction energy results showed that PCl₃@C₆N₈ (−23.45 kJ/mol) is more stable than PH₃@C₆N₈ (−14.79 kJ/mol). A considerable decrease in the HOMO-LUMO band gap of C₆N₈ was observed as a result of its complexation with the analytes. QTAIM and NCI analyses indicated the presence of weak noncovalent interactions between C₆N₈ and gases (PH₃ and PCl₃). SAPT0 analysis was performed to quantify the NCIs. MEP maps of complexes revealed the localization of electronic density on C₆N₈. The little recovery time of complexes (determined at 300 K) showed that C₆N₈ can serve as a reusable sensing material against PH₃ and PCl₃. Our results demonstrate that the C₆N₈ surface is a reliable material for detecting phosphine and phosphorous trichloride gases.

Asymmetric deformation density analysis is applied on bilayer graphene flakes as molecular capacitors to identify the extent of asymmetric distribution of electrons and holes when exposed to bias voltage. Three triangular, orthorhombic, and hexagonal symmetries for graphene flakes are considered in two sizes and electric field potential is applied along the vector perpendicular to graphene flakes' plane to simulate 1–4 V as the bias voltage applied to molecular-scale capacitors The number of electrons responsible for asymmetric distribution of electrons and holes, and occupied to virtual transfer are calculated, and electric field deformation density analysis is also performed that shows distributions of electrons and holes are quite asymmetric for the orthorhombic symmetry, while for the other symmetries, they are almost image of each other. It was found that isosurfaces of deformation density distribution possess a multilayer structure and accretion and depletion of electrons can be taken place between flakes or outside the parallel flakes, and it is shown that bias voltage is able to significantly remove symmetry of electrons and holes distribution. Inspection of molecular orbitals showed that electric field could change the energetic order of molecular orbitals, so that occupancy inversion is occurred for the orthorhombic systems that is responsible for their extraordinary properties.

A polymer is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. The bulky and normal polymers are graphs of aromatic organic compounds. The main idea of this article is to elaborate the expected results of Zagreb connection, sombor and reduced sombor indices in bulky and normal polymers. The generalized expected results with the help of probability technique for all the chains like polyonino, pentachain, polyphenyl, cyclooctane cyclodecane and so on different chains for Alkanes have been determined which are connected with and without any bond (edge). The Sombor topological index is named after the city of Sombor in Serbia, where it was introduced by a group of researchers in the field of chemoinformatics and mathematical chemistry. At the end, we have find the meta, ortho and para polymers to define the average values of Zagreb connection, Sombor and reduced Sombor indices.

In this study, BF₂ complexes of pyridyl-isoindoline-1-ones (BPIO) has been firstly designed and investigated as an excellent corrosion inhibitor for the mild steel in 1 M HCl. The corrosion protection properties of BPIO were studied by using a series of experiments. The results indicated BPIO has excellent inhibition performance, and inhibition efficiency of BPIO reached up to 96.6%. The effects of immersion temperature and time were investigated by weight loss experiments to evaluate the stability of adsorbed BPIO film in protecting steel surface. Based on potentiodynamic polarization studies, BPIO acted as one mixed-type corrosion inhibitor with predominant anodic effectiveness, and its adsorption on the mild steel follows the Langmuir adsorption isotherm. The values of ΔG_ads suggested the adsorption of BPIO on the mild steel surface was through a combination of chemisorption and physisorption. The adsorption of BPIO molecules on the steel surface was further identified by the techniques of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The quantum chemical calculations based on density functional theory (DFT) and molecular dynamics (MD) simulations were used to optimize the BPIO molecular structure and investigate the inhibitive properties on the theoretical level, which agreed well with the experimental results. Besides, BPIO has been used for the development of water soluble metal antirusting agent.

S. Mohebbi, F. Shafiei, T. Momeni Isfahani, M. Ahmadi Sabegh, Int. J. Quantum Chem. 2024, 124(1), e27314. https://doi.org/10.1002/qua.27314.

In the address section (below the name of authors), the full name of university “Department of Chemistry, Science Faculty, Islamic Azad University, Arak, Iran and Department of Chemistry, Science Faculty, Islamic Azad University, Ahar, Iran.” and also Correspondence address “Fatemeh Shafiei, Department of Chemistry, Science Faculty, Islamic Azad University, Arak, Iran.” were incorrect. These should have read: “Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran and Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran.” and also Correspondence address “Fatemeh Shafiei, Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran.”

We apologize for this error.

Present calculations reveal that complexation with a Lewis acid such as BH₃ dramatically increases the strength of hydrogen bonding between H₂O, H₂S, HF, HCl, and NH₃ dimers. The increase in strength is attributed to the increase in electrostatic component. The interaction energies were found to increase by two to three folds (more than 50% increase in interaction energies). Detailed electronic structure analyses within the realm of quantum theory of atoms in molecules and non-covalent interaction index confirms the strengthening of hydrogen bonding due to Lewis acid complexation. Decomposition of interaction energies using symmetry adapted perturbation theory reveals that the increase in interaction energy (more than 60%) is due to the dramatic increase in electrostatic component.

The kinetic and mechanistic studies for the reaction of hydroxyl radical with two quinoline based herbicides, namely, quinclorac and quinmerac has been performed using various computational methods in aqueous media. Geometry optimizations were performed using Density Functional Theory (DFT) methods including water as the solvent. Local reactivity parameters of these herbicides towards the ^•OH radical are predicted using condensed Fukui function. Single point energies of various species were calculated using double hybrid method, namely, B2PLYP–D for better accuracy. The pK_a values for these acid based herbicides allow them to exist in deprotonated form in aqueous condition. Hence, the calculations are also performed for the deprotonated or the anionic form apart from the neutral species. Individual rate coefficients for ^•OH radical addition reaction with each carbon atoms were evaluated using conventional transition state theory using one–dimensional tunneling corrections. The solvent effect on reaction is implemented through Collins–Kimball formulations. Both the approaches, namely, the Fukui index and individual rate constant determination confirms that the most reactive site for the ^•OH radical addition in these two herbicide is the carbon atom attached to the COOH group. The total rate constant for the ^•OH radical reaction with both neutral and anionic forms of these two herbicides are relatively high and equal to its diffusion-limit value. Evaluation of the ecotoxicities of the parent herbicides and their OH adducts is estimated using the structure–activity relationship concept.

In this work, a comparative study of four functional forms used to represent potential energy curves (PECs) is presented. The starting point is the Hulburt-Hirschfelder, followed by the Extended Rydberg potential function, ending with two of the most recent potentials presented in the literature for diatomic systems: the Araújo-Ballester potential and the Improved Extended Lennard-Jones potential. The chosen potentials have in common the fact that all their parameters are algebraically calculated, without any fitting procedure, and all of them have direct dependence on Dunham's parameters. The mathematical behavior of these functions for the short- and long-range regions is discussed. As study case, the diatomic system $��\text{CO}�$ in its ground electronic state was selected. To quantify the accuracy of the potential energy functions, the least-squares Z-test method, proposed by Murrell and Sorbie, is used. Furthermore, the main spectroscopic constants and vibrational energy levels are calculated and compared for all potentials.