International Journal of Quantum Chemistry最新文献

The structural and electronic properties of Aucubin, a bioactive iridoid glycoside, were thoroughly investigated using Density Functional Theory (DFT) with the B3LYP functional and the 6-311++G(d,p) basis set. Geometry optimization, energy computations, and electronic characteristics were determined, yielding an ultimate energy value of −1261.3556 Hartree. Natural atomic charges (NAC), frontier molecular orbitals (FMO), and molecular electrostatic potential (MEP) maps were examined to elucidate the compound's reactivity and stability. Additionally, simulation-based spectroscopic analyses, including FTIR, UV–Vis, and NMR, were performed to characterize the vibrational and electronic transitions of Aucubin. The findings indicate a narrow HOMO-LUMO gap (0.16189 a.u.), suggesting significant chemical reactivity and potential applicability in photonic communication devices. This comprehensive study enhances our understanding of Aucubin's structural and electronic properties, paving the way for future applications in pharmaceutical and photonic fields.

The structures and binding energies of the Be²⁺·(N₂)_n complexes have been determined utilizing the CCSD/aug-cc-pVTZ computational method. For the mono- and di-ligated complexes, a linear configuration was observed, while tri- and tetra-ligated complexes exhibited trigonal planar and tetrahedral geometries, respectively. The sequential bond dissociation energies for these complexes were calculated, revealing a specific hierarchy: Be²⁺·N₂ > Be²⁺·(N₂)₂ > Be²⁺·(N₂)₃ > Be²⁺·(N₂)₄. This sequence corresponds to the variations in the strength of the ion-quadrupole interaction energies present in these complexes. Bond analysis of these complexes indicates that σ-donation is the primary factor influencing the observed trend in the sequential bond dissociation energies.

This study presents an automated framework for discovering Diarylethene derivatives with specific HOMO-LUMO bandgaps by integrating first-principles calculations with evolutionary optimization algorithms. We develop a protocol for performing automatic, parallel Density Functional Theory calculations using Turbomole, enabled by the Atomic Simulation Environment Python wrapper. This integration allows for fully autonomous evolutionary searches, removing the need for human intervention. To evaluate our platform, we conduct searches within the chemical space of Diarylethene using two optimization strategies: A “local” strategy, which explores local neighborhoods, and a “glocal” strategy, which combines local exploration with memory of past achievements.

The dipole polarizability and hyperpolarizability of the hydrogen atom confined in spherical Gaussian potential under the influence of an external electric field are calculated within the sum-over-states framework, where all system eigenenergies and wave functions are obtained using the generalized pseudospectral method. It is interestingly found that the Gaussian potential produces a stronger suppression effect on the hyperpolarizability than on the polarizability, especially at moderate values of confinement radius. By analyzing the second- and fourth-order energy corrections for the ground state of the hydrogen atom under an external electric field, we define the maximal electric field strength where the perturbation approximation of the field–atom interaction is applicable. Based on the accurate ground state energies, polarizabilities, and hyperpolarizabilities, as well as the corresponding $��Z�$-scaling laws, the Stark shifts of hydrogenic ions confined in Gaussian potentials are estimated over a wide range of confinement radius and potential depth.

In the present study, a novel strategy for constructing new cage energetic compounds with both high energy and low sensitivity was proposed. That is to use a 3D nitrogen-rich cage compound as the core parent molecule to set the basis for obtaining high energy, followed by the introduction of a moderate number of nitro groups into the cage, which are linked with the carbon atoms to further improve the energy without increasing the sensitivity obviously and controlling the reaction difficulty caused by too many nitro groups as low as possible. The amino groups were introduced into the structure also to adjust the balance of energy and sensitivity. Finally, more importantly, the formation of nitrogen-rich cage and the introduction of nitro/amino groups were achieved synchronously by a typical and attractive one-step reaction (The Diels–Alder reaction) which possesses 100% atomic efficiency. Based on this strategy, six series of amino-substituted nitrogen-rich azoles were used as the dienes to react with different dienophiles like tetranitroethylene (TNE) to form the final cage products. From the theoretical investigation results, five optimal compounds (PA0, PB0, PC0, PE0, PE1) with low reaction energy barrier (11.2–31.6 kcal/mol) may set the high energy of CL-20 and low sensitivity of TNT together, and have been screened out as new advanced energetic compounds successfully. This study may provide a new feasible strategy and a unique perspective for developing new advanced energetic compounds.

The stability of a model two-electron system with tunable interelectronic repulsion has been explored with respect to a scaling parameter $��\kappa �$. The complex scaling method within an orbital-based configuration expansion and the Ritz variational method with an explicitly correlated Hylleraas-type basis set are considered for this purpose. An estimation of critical scaling parameter $��{�\kappa �}_{�c�}�$, at which the bound state transforms into a shape resonance state, is reported. The position and width of the quasibound state for $��\kappa �>�{�\kappa �}_{�c�}�$ are calculated by adopting the complex scaling method. The onset of quantum phase transition in the vicinity of $��{�\kappa �}_{�c�}�$ is discussed through the estimation of geometrical properties such as radial moments.

Wogonin and wogonoside are derived from the traditional Chinese medicine Scutellaria baicalensis. Due to their various biological activities, the research on their various properties has simulated great interest. In this work, we systematically and theoretically studied the intra- and inter- interactions of wogonin and wogonoside. For intra- interactions, their details were exhibited with the help of IRI, BO, and LOL-π. To predict inter-interactions, the results of ESP, van der Waals potential, and hydrogen and hydrophobic interactions were shown. Our meaningful research results will provide theoretical guidance for more efficient utilization of wogonin and wogonoside for corresponding studies, and will help confirm the structure–activity relationship, an essential topic nowadays, of these two molecules.

Reaction free energies of hydrogen peroxide (H₂O₂) and hydrated transition metal ions to form hydroxyl radical, which is known as Fenton or Fenton-like reactions, are calculated by DFT methods. Standard electrode potentials of M²⁺/M³⁺ (M = Ti, V, Cr, Mn, Fe, Co) in aqueous solutions are calculated as benchmarks for the selected hybrid functionals and the basis sets. Mean absolute errors of the calculated redox potentials are comparable to those of the previous DLPNO-CCSD(T) calculation in most of the combinations. In contrast, calculated Gibbs free energies of hydroxyl radical formation are dependent on the choice of the functionals, and PBE0 gives the best results. The effect of anion substitution in the first hydration shell and Fenton-like reactions of other metal ions (Ti³⁺, V²⁺, Cr²⁺, Mn²⁺) are also examined.

LaTaON₂ is a promising visible-light-responsive photocatalyst for water splitting because of its broad visible light absorption and suitable band edge positions. However, the high defect concentration hinders the charge transfer and results in the poor photocatalytic performance of LaTaON₂. Loading proper cocatalysts is one of the most efficient strategies for promoting charge separation/transfer and achieving high reaction activity. In this work, we have used density functional theory calculations to study the depositions of Pt, Ru, and Ni single atom cocatalysts on LaTaON₂(010) surface. The most stable adsorption configuration is the same site for all the elements, namely the top of the N atom on the La-terminated surface and the fourfold hollow site on the Ta-terminated surface. The adsorption of the metal single atom on Ta-termination is stronger than that on La-termination due to the formation of more bonds. Upon the deposition, no localized impurity states appear in the middle of the forbidden gap since the nd states of metal adatoms are located within the valence band and conduction band of LaTaON₂. The efficiency of the photocatalysts is probed by investigating their ability to adsorb the H atom in a thermodynamically favorable manner. Our results reveal that the energetically favorable sites of HER are the N atom on the La-termination and the O and N atoms on the Ta-termination, respectively. Compared with the clean surface, the surfaces with Pt, Ru, and Ni single adatoms exhibit higher performance for HER because loading metal cocatalysts can further activate the surface nonmetal atoms and reduce the Gibbs free energy of hydrogen adsorption. The work gives an atom-level insight into the role of metal single atom cocatalysts in the LaTaON₂ photocatalyst for hydrogen production.

This manuscript introduces a relativistic method to determine the electronic structure and electron collision ionization process of atoms placed in a semiclassical plasma. The method uses the effective interaction pseudo-potential derived for general two interacting charged particles taking into account the quantum mechanical and screening effects to model the plasma environment. The Dirac equation with the aforementioned pseudo-potential is solved numerically to obtain the bound state and continuous state wave functions. The method starts from the Dirac equation and thus includes the relativistic effects on the one-electron level. The effects coming from the Breit interaction and quantum electrodynamics corrections are included. As a representative example, we investigate the plasma electron screening effect and the plasma ion screening effect, separated and combined, on the level delocalization and electron collision ionization process of hydrogen atoms placed in a strongly coupled semiclassical plasma environment. Properties of the spectra such as energies, oscillator strengths, and relativistic energy shifts corresponding to bound states are determined. The relativistic distorted wave method is used to provide a consistent and elaborate description of the ionization cross sections of the electron collisions involved. Our results reveal that the plasma electron shielding effect contributes to a reduced ionization potential and oscillator strength, while increasing the electron impact ionization cross section, when compared with the results of an isolated scenario. When the plasma ion shielding effect is included, these observed alterations are further enhanced, highlighting the considerable role of the plasma ion shielding effect in this process. Our results are in agreement with other theoretical data. The present study not only extends the relativistic distorted wave approach to the analysis of collision processes in semiclassical plasmas and evaluates the impact of the plasma ion screening effect but also has practical implications for radiation physics, inertial confinement devices, and the interiors of stars.