International Journal of Quantum Chemistry最新文献

Twist angle between adjacent two-dimensional (2D) materials can provide an exotic degree of freedom and lead to superior properties such as fascinating electronic structure, tunable bandgaps, and excellent carrier transport. The electronic and optical properties, and quantum capacitance of AA1 and AA2 stackings of twisted III-nitride bilayers AlN, BN, and GaN at a 21.79° twist angle are investigated by density functional theory (DFT). Compared with no-twisted systems, the twisted angle drastically reduces the band gaps of bilayer systems. The stacking mode is sensitive to the electronic structures of twisted bilayer AlN, but insensitive to the electronic structures of twisted bilayers BN and GaN. Flat bands of twisted bilayers AlN and GaN are introduced after atomic reconstruction and mainly originate from N-p states, especially for AA2 stackings of twisted bilayers AlN and GaN. Twisted bilayer BN has the strongest absorptions of 16.4% for AA1 stacking and 14.8% for AA2 stacking in the ultraviolet region. Electrical conductivity is insensitive to stacking modes, and twisted bilayer GaN possesses the strongest electrical conductivity. Different stacking modes have little impact on the electrode type of twisted bilayer materials. All systems are cathode materials at the whole voltage. Effective mass and work function are further studied.

This work presents an improved version of the residual vector correction (RVC) algorithm, designed to address the eigenproblem involved in electronic structure calculations. Instead of directly diagonalizing the entire Hamiltonian matrix, the proposed algorithm iteratively diagonalizes a 2 × 2 submatrix, focusing only on the relevant molecular orbitals. Molecular orbital energies are iteratively minimized along a residual vector, with the step size determined by diagonalizing the 2 × 2 submatrix. To obtain the subsequent eigenvalues, we employ Hotelling deflation, which constructs the necessary auxiliary Fock matrix. Since the size of the diagonalized matrix does not increase with the molecular system, this algorithm eliminates the cubic scaling dependence of computational efficiency on molecule size seen in direct diagonalization. Compared to the earlier version, the implementation within the Hartree–Fock framework shows that the current version is significantly more practical for the calculation of considerably large molecules. As demonstrated, the RVC method consistently surpasses existing iterative approaches in efficiency while maintaining high accuracy.

Lithium-ion batteries (LIBs) have dominated the energy storage field due to their high energy density, long cycle life, and environmental friendliness. In this study, we systematically investigated the electrochemical properties of phosphorus (P)-doped γ-graphyne as a promising LIBs anode material using density functional theory calculations. The formation energy and cohesive energy of γ-graphyne at varying doping concentrations are calculated, demonstrating excellent experimental synthesizability of P-doped γ-graphyne. Notably, the P-doped system exhibits enhanced electrical conductivity compared to pristine γ-graphyne. The adsorption energy of a single lithium (Li) atom on P-doped γ-graphyne is determined to be −3.72 eV, significantly higher than those of N-doped, Si-doped, and intrinsic γ-graphyne. Even with increasing Li storage, the Li adsorption energy remains greater than the cohesive energy of bulk lithium, while the average open-circuit voltage falls within the optimal range of 0–1 V, ensuring high operational safety. Remarkably, the theoretical Li storage capacity of P-doped γ-graphyne reaches 1150.68 mAh/g, which is 1.85 times that of pristine γ-graphyne and 3.09 times that of conventional graphite. Furthermore, the diffusion barrier calculations reveal that P-doped γ-graphyne substantially reduces the Li-ion migration energy barrier, indicating favorable lithium diffusion kinetics. In summary, P-doped γ-graphyne demonstrates exceptional advantages in specific capacity, structural stability, electrical conductivity, and Li-ion diffusion kinetics, providing critical theoretical insights and experimental guidance for designing next-generation high-performance LIBs anode materials.

The molecular properties of 2-(2-Bromophenyl)-1H-benzimidazole (BPBZ) were calculated using the DFT-Becke-3-Lee-Yang-Parr functional and 6-311++G(d,p) basis set. The assigned vibrational wave numbers, the observed FT-IR and FT-Raman spectra accord fairly well. Frontier molecular orbitals and Mulliken charges were used to examine the energy gap and charge transfer interaction of the molecule. The total, partial density of states (TDOS and PDOS) and overlap population density of states (OPDOS) spectra have been computed. Using natural bond orbital analysis (NBO), the intramolecular stabilization interactions of the molecule have been evaluated. The electrophilic and nucleophilic reactivity sites were examined by the molecular electrostatic potential surface and the Fukui function. We have established whether a chemical is suitable to be a drug by using molecular docking with estrogen sulfotransferase receptor (binding energy of −8.5 kcal/mol) and ADMET prediction. The molecule's cytotoxicity (IC₅₀ = 15.17 μg/mL with MCF-7 breast cancer cell line) and antibacterial properties have been done.

Aiming at the aqueous chemistry of the cadmium ion (Cd²⁺), this study systematically investigated the aqueous configurations and thermodynamic stabilities of Cd²⁺ and its hydrolyzed species with different coordination numbers, by using various combinations of quantum chemical calculation methods and implicit solvation models. The results reveal that the implicit solvent model exerts a notable influence on the structures and energies of Cd²⁺ ion and its hydrolyzed species, as well as the predicted pK_a values. The combination of PBE0-D3(BJ), M06-2X, and wB97XD functionals with the IEF-PCM model (employing UA0 radii) effectively simulates the aqueous configurations of Cd²⁺ hydrates and hydrolyzed species. Meanwhile, the MP2 method, the double-hybrid functionals B2PLYPD3 and mPW2PLYPD, coupled with either the IEF-PCM model (utilizing Pauling or Bondi radii) or the SMD model, yields Cd²⁺ hydrolysis pK_a values that closely matching experimental data. The results indicate that the aqueous Cd²⁺ ion primarily exists in the form of hexahydrate Cd(H₂O)₆²⁺, and its hydrolyzed species, Cd(OH)_m^(2-m)+ (m = 1–4), mainly exist as tetracoordinate Cd(OH)(H₂O)₃⁺ and Cd(OH)₂(H₂O)₂⁰, tricoordinate Cd(OH)₃⁻, and tetracoordinate Cd(OH)₄²⁻, respectively. The study is expected to provide valuable references for systematically studying the interactions between Cd²⁺ and other inorganic ligands in aqueous systems.

A series of K-6 based energetic compounds are designed by the addition of the characteristic structures of NQ and FOX-7. Density functional theory calculations at the B3LYP/6-311G(d,p) level are performed to predict the frontier orbital energy, heats of formation, detonation performance, and impact sensitivity of the designed compounds. It is found that compound C3 possesses the highest value of ΔE_LUMO-HOMO (5.24 eV), whereas that of compound E6 is the lowest (2.86 eV). Compound C4 has the highest values of ΔH_f,solid (1768.0 kJ mol⁻¹) while that of compound D5 possesses the lowest values (431.1 kJ mol⁻¹). It is concluded that the addition of the N₃ group combined with the tetrazole ring and NQ structure can improve the values of heats of formation effectively. It is also found that compounds F2 and B3 possess the maximum and minimum values of D and P (compound F2: D, 9.65 km s⁻¹, P, 44.0 GPa; compound B3: D, 7.60 km s⁻¹, P, 25.0 GPa). There exist 24 compounds that possess higher values of h₅₀ than that of RDX, whereas there are 16 compounds that possess higher values of h₅₀ than that of HMX. Finally, compounds A7, A8, and D1 are screened as potential high energy density compounds. Their frontier orbital distribution, thermodynamic properties, electrostatic potential distribution, and area are simulated to give a full understanding of the electronic structure and physicochemical properties of the screened compounds.

Breast cancer is the most diagnosed cancer in women globally, with millions of new cases each year. AKT-1 plays a significant role in the development and progression of breast cancer, as it is a critical part of the PI3K/AKT/mTOR signaling pathway, which regulates several cellular processes. The current work was focused on assessing the structural stability and reactive potential of allyl sulfide using density functional theory method, and geometric parameters were calculated. IR and Raman frequencies were simulated, and the vibrational wavenumbers were examined. The electronic spectroscopy was determined in the gaseous phase through TD-DFT technique, and the transition allotted for allyl sulfide was σ → σ*. The calculated energy between HOMO and LUMO was 5.597 eV, confirming better stability of allyl sulfide. Allyl sulfide's electrophilic and nucleophilic characteristics, reactive zone, charge distribution across atoms, and topological properties were studied. The drug-likeness attributes of allyl sulfide were confirmed through pharmacophore studies, confirming its safety profile. Docking experiments showed that allyl sulfide had a higher binding score with the AKT-1 protein (−6.8 kcal/mol). Molecular dynamics simulation was used to evaluate the stability of the AKT-1 and allyl sulfide complex throughout a 100 ns run. The MTT assay revealed the cytotoxic effect of allyl sulfide in T47-D cells. The effectiveness of allyl sulfide as a breast cancer treatment was assessed using in silico and in vitro techniques, including docking, MD simulation, MTT assay, and the ADMET study to reveal drug safety features.

Rising concentrations of nitrogen monoxide (NO) in the atmosphere have posed significant environmental risks. Conversion of NO to NO₂ is a promising oxidation strategy for reducing NO levels. Therefore, in order to comprehend the oxidation mechanism of NO into NO₂ at the molecular level, we employed density functional theory (DFT) with the M06L functional and the def2TZVP basis set. Pristine and doped anionic [Au_nPd_3–n]⁻ (n = 0–3) clusters were chosen, as gas-phase anionic Au clusters serve as ideal models for mimicking gold catalysts due to their electronic structure, which closely resembles that of active supported gold catalysts. We explored the detailed reaction pathways under the Langmuir– Hinshelwood (LH), termolecular Eley–Rideal (TER), and termolecular Langmuir– Hinshelwood (TLH) mechanisms, where two NO molecules are oxidized to two NO₂ molecules using molecular O₂. Our findings indicate that doping Pd onto anionic [Au₃]⁻clusters enhances the adsorption of both NO and O₂. The calculations demonstrate that the Pd site on bimetallic clusters is more preferable for adsorption than that of the Au site. Moreover, the energetic span model reveals that the [Au₂Pd]⁻cluster is the most efficient cluster for converting NO to NO₂ via the L-H mechanism.