International Journal of Quantum Chemistry最新文献

A diverse set of promising donors for donor–acceptor chromophores based on dihydro-1H-pyrazole (pyrazoline) for use in electro-optics was investigated using DFT at M06-2X/aug-cc-pVDZ level of theory. These calculations showed that it is possible to achieve a molecular hyperpolarizability of up to 1700*10⁻³⁰ esu (up to three times higher compared to conventional diethylaniline donors) for a simple tricyanofuran-based acceptor by carefully tuning the donor structure. It was shown that the molecular hyperpolarizability is mainly affected by the substituents in the aryl rings in positions 3 and 1 of the pyrazoline cycle, while the substituents of the aryl ring in position 5 and the pyrazoline ring itself can be varied without significant effects on the hyperpolarizability. For one of the compounds, a detailed study of the lowest energy electronic excitation was performed using the TD-DFT, confirming the role of the pyrazoline ring as a secondary donor.

Geometries and electronic properties associated with relative stabilities and energy gaps of porous (InP)_12n (n = 1–12) nanoclusters (NCs) (nanowires and nanosheets) are systemically studied by density functional method. The relative stabilities of (InP)_12n NCs through the calculated fragmentation energies and cluster-binding energies are determined and discussed. Interestingly, the calculated energy gaps of (InP)_12n nanowires and nanosheets are localized at regions of visible light energy ranges. (InP)_12n are relatively wide-band semiconductor solar energy nanomaterial. The calculated density of states reveals large-sized porous (InP)_12n nanosheets and nanowires with narrow pore size distribution and slight thickness and a large surface area manifest ultrahigh specific capacitance of trapping solar light energies and high light-to-electricity conversion efficiencies in solar energy absorption or conversion or photovoltaicsm. Particularly, (InP)_12n NCs maintain their elemental properties of individual (InP)₁₂ clusters in the energy gaps of (InP)_12n (n > 4). NCs are almost independent of variable sizes. Specifically, the size-dependent charge transfers of In atoms in (InP)_12n NCs exhibit that ionic and covalent bonding exist in (InP)_12n NCs and can stabilize (InP)_12n NCs. Comparison with experiment results available is made.

This paper presents a comprehensive approach for designing polymer acceptors for organic photovoltaic applications through the generation of an extensive database and the application of machine learning (ML) techniques. Over 40 ML models are trained for the prediction of power conversion efficiency (PCE). Histgradient boosting regressor has appeared as best model. Almost 10 k polymers are generated and their PCE values are predicted. The chemical space of polymers has been visualized and analyzed. Cluster analysis revealed significant differences among the selected polymers. Additionally, an assessment of synthetic accessibility for these polymers indicated that the majority can be synthesized with relative ease.

The 2,2,5-trimethyl-1,3-dioxane-5-carboxylic acid (TDCA) using both theoretical and experimental methods have been studied. The sample has been subjected to XRD, FTIR, FT-Raman, (C¹³ and H¹) NMR, and UV–vis spectrum analysis. Then, theoretical calculations have been performed at the DFT/B3LYP/6-311++G(d,p) higher based scale. The theoretical and experimental geometrical parameters and frequencies have been compared well. Theoretical and experimental NMR chemical shifts have been determined. Absorption wavelengths of UV–Vis spectrum were experimentally measured and compared with TD-DFT predictions. Detailed explanations have been given for frontier molecular orbitals, low density gradient, distribution of Mulliken charges, molecular electrostatic potential (MEP), RDG, localized orbital location, and electron localized activities. Based on the studied 2D image of the Hirschfield surfaces, H···H (65.6%) and O···H/H···O (33.6%) are found as the controlling interactions. A high binding affinity of −6.5 Kcal/mol has been calculated against 4OAR protein. These theoretical findings of the molecule may be used as an anticancer drug candidate, which helps to explain the structural stability, reactivity and anticancer potential of TDCA. High drug affinity for the TDCA has been detected by in silico ADMET prediction.

1, 1′-azobis-1, 2, 3-triazole (C₄H₄N₈, N8) is a novel nitrogen-rich energetic material with excellent detonation performance, which has received widespread interest. Inspired by recent theories and experiments, the dependence of structural, vibrational, and electronic properties on high pressure up to 10 GPa was systematically investigated using periodic DFT calculations. It was found that the optimized structure belonged to the cis-N8 structure through comparing the theoretical IR with experimental IR spectra. The third-order Birch–Murnaghan equation of state for N8 was obtained up to 10 GPa, where the bulk modulus and its pressure derivative were 10.91 GPa and 7.689, respectively. More importantly, the pressure dependence of Laplacian bond order indicated that the five-membered ring opening was the first step in the decomposition process, and that high pressure could inhibit the decomposition process of N8 due to the reinforcement of non-covalent interactions. The present work could deepen the understanding of the energetic materials N8 under high pressure, and is of great significance to the blasting and detonation applications of N8.

The development of high-performance ion battery anode materials is conducive to the rapid development of urban rail transit. Based on first-principles calculations, this paper studies the potential performance of the recently discovered two-dimensional material SnSe₂ as a negative electrode for zinc ion batteries. By calculating the adsorption energy, the most stable adsorption configuration of Zn was determined. The band gap of intrinsic SnSe₂ decreases after strain, which promotes the transition of carriers. The band gap opens after the strain occurs in the Zn adsorbed SnSe₂ system (Zn-SnSe₂), which confirms the regulation of strain on the band gap. The lowest diffusion barrier of Zn is 0.083 eV. The theoretical zinc storage capacity is calculated to be 387.550 mAh/g. The calculation results provide theoretical parameters for the application of SnSe₂ in ion batteries.

In this work, the author attempted to develop a Shannon wavelet-based numerical scheme to approximate the information entropies in both configuration and momentum space corresponding to the ground and adjacent excited energy states of one-dimensional Schrödinger equation appearing in non-relativistic quantum mechanics. The development of this scheme is based on the judicious use of sinc scale functions as an approximation basis and a suitable numerical quadrature to approximate entropies in position and momentum spaces. Priori and posteriori errors appearing in the approximations of wave functions and entropy integrals have been discussed. The scheme (coded in Python) has been subsequently exercised for various exactly solvable and quasi-exactly solvable non-relativistic quantum mechanical models in confined domain.

Breast cancer is a leading cause of cancer-related morbidity and mortality among women globally. It arises from the abnormal proliferation of cells within breast tissue and can manifest in several subtypes, classified by the expression of hormone receptors. The main objective of this work is to assess the effect of solvent on 2-methoxy-4-allylphenol's (2M4AP) in quantum chemical calculations and ability of 2M4AP to bind with the proteins associated with breast cancer. The non-toxic nature of 2M4AP was initially validated through drug-likeness studies and it complies with Lipinski's criteria. The optimization of 2M4AP structure was carried out in gas and liquid phase in DFT technique with B3LYP/6-311++G (d, p) level. Then the electronic spectrum was calculated in TD-DFT technique and the transition was determined to be n → σ*. The steadiness, charge dispersal and electronic properties were assessed and the band energy value was calculated to be 5.58 eV (gas) and 5.64 eV (liquid), exhibiting a stable confirmation of 2M4AP structure. Topological characteristics exhibited the intermolecular connections of 2M4AP along with electronic features. From the simulated results, the effect of solvent (water) in 2M4AP was very minimal and the structure is stable in both gas and liquid phase. Further, the docking studies, 2M4AP exhibited highest binding score of −7.3 kcal/mol with progesterone receptor, confirming the better ability of 2M4AP to react in hormone-positive breast cancer. The Ramachandran plot confirms the stability of interacted amino acids with the ligand molecule. Thus, 2M4AP can be considered as a potent candidate for treatment of breast cancer after clinical studies.

We have explored the chelation of dimethylglyoxime ligand to divalent (nd^x: x = 6, 7, 8) transition metal (TM) cations in two media (gas phase and water) at the B3LYP//LANL2DZ/6–311+G (d,p) and B3LYP/def2-TZVP level at lower multiplicity and higher multiplicity states. Majority of the 18 optimized halide (chloride and bromide) complexes prefer square planar configuration. The correlations discerned between the experimental structural data and their estimated counterparts demonstrate a good credibility for complexes at lower multiplicity state. The basis set superposition errors (BSSEs) estimated is very small which reflects the fact that the choice of different basis sets (B3LYP//LANL2DZ/6–311+G (d,p)) introduces a slight bias in the calculation of energies. The ADMP (atom-centered density matrix propagation) simulations in water on chloride complexes indicate the irreversible nature of these M—N dissociation in trajectory simulation process. This fact explains our exclusive focus on the examination of the [glyoxime ligand]…[MX₂] interactions. In addition, the solvation of (3d and 4d) transition metal chloride complexes causes a sensitive augmentation of the metal ion affinity (MIA) with an average of 0.29 and 0.24 kcal/mol. In both multiplicity states, the topological parameters have illustrated that the M—N and M—X bonds are typical metal–ligand in both media. The average ΔE_orb/ΔE_steric ratio equal to 0.45 and 0.11 in gas phase and water, respectively, reveals the predominance of the contributions from non-covalent bonding interactions (NCI) compared to those of covalent bonding. But, the maximal value equal to 6.760 is obtained for bromide rhodium complex in water. NBO analysis in both media highlights the fact that a more pronounced ionic character is observed for the majority of the chloride complexes at both spin multiplicity states because of their higher retained charges on the metal atom. For [dimethylglyoxime]…[MX₂] interaction (X = Cl and Br), the charge decomposition analysis demonstrates that the lowest value of the d/b ratio is found for the chloride platinum complex at lower multiplicity state in water. This is a proof of its strong relativistic effects.

The spectral-luminescence properties and photochemical conversions of phenol were analyzed for an isolated molecule as well as in water solvents in a continuum implicit model and explicit atomistic surroundings. This involved employing cut-edge hybrid quantum-classical methodologies to generate static optical spectra and the excited dissipative crossing potential energy curves. A combination of electronic excitations, gradient calculations, and embedding electrostatic potential fitting charges on quantum-classical molecular dynamic propagation trajectories provided statistically averaged absorption spectra. The mixed-reference spin-flip multiconfigurational linear response method based on reference triplet preprocessed in the time-dependent density-functional theory was utilized to determine conical intersections between the lowest excited and ground states, as well as two-stage transitions from the second excitation to the ground state. Non-adiabatic quantum-classical molecular dynamics defined photodissipative trajectories of excited states, their lifetimes, and crossing points through trajectory surface hopping together with the mixed-reference spin-flip and embedding electrostatic potential fitting approaches. Dyson orbitals of the extended Koopmans' theorem were applied to reveal the nature of molecular states at conical intersections and key points on photodynamic trajectories. Potential hydroxyl group cleavage predicted with conical intersections searching turns to “swift” OH deprotonation through |π→$��{\sigma }_{\mathrm{OH}}^{*}�$⟩ transition along photodynamic propagations in contrast with “long” processes leading to benzene ring deformation with stable OH bond.