This work reports the magnetic index of aromaticity of cyclophosphazene (-PNH) and their halogenated cyclic derivatives: -PNF, -P
This work reports the magnetic index of aromaticity of cyclophosphazene (-PNH) and their halogenated cyclic derivatives: -PNF, -P
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 pKa 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 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.
This study presents an in-depth inquiry into estimating ADME properties for promising anticancer drugs, particularly amino acid-based alkylating agents, through ev-ve degree topological indices and QSPR analysis. The aim of the study is to compare multigraph modeling to simple graph modeling in estimating six ADME properties. Results demonstrate that multigraph modeling's superior performance, with notable high correlations such as for maximum passive absorption (MPA) using the M-ev index, compared to simple graph modeling's with the -ev index. This emphasizes the need for sophisticated modeling techniques in drug development. The primary objective is to compare multigraph and simple graph modeling using topological structure descriptors, followed by QSPR analysis to determine the better approach in estimating ADME properties. MCDM weight allocation techniques validate correlation values, enhancing understanding of estimators and identifying potential drugs. This underscores the importance of considering various MCDM methods and weight allocation approaches for reliable decision-making in healthcare contexts.
In the present work, we present an investigation of Collins Conjecture, a hypothesis made by D. M. Collins in 1993 relating correlation energy and entanglement entropy, by calculating the ground state and singly-excited triplet-spin 1s2s 3S and 1s3s 3S state energies of the helium iso-electronic sequence, with Z = 2–15. By using extensive orthonormal configuration interaction (CI) type wave functions with B-Spline basis up to about 6000 terms, linear entropy and von Neumann entropy for the abovementioned atomic systems are determined. Together with the Hartree-Fock energies obtained following a self-consistent field theory, we have found that there exist linearly proportionalities between the renormalized correlation energies and entanglement entropies of both linear and von Neumann, showing a support for Collins Conjecture applicable to the ground and singly-excited triplet-spin states in the helium sequence, for a range of finite Z-values.
Exploring suitable catalysts to catalyze the chemical transformation of CO2 molecules is essential to reduce CO2 levels. In this article, catalyst models of Fe-C4, Fe-N4, and Fe-Si4 were constructed using the density functional theory (DFT) calculations, and the reaction mechanisms of CO2 hydrogenation over these three catalysts were calculated and analyzed. The results showed that the doping of N atoms lowered the energy barrier of the second hydrogenation step compared with that of Fe-C4 catalyst, while the doping of Si atoms changed the electron distribution on the surface of the catalyst and formed new Si adsorption sites. And the Fe-Si4 catalyst had a stronger ability to activate CO2 molecules as well as stronger catalytic performance compared with the Fe-C4 and Fe-N4 catalysts, which was mainly attributed to the synergistic catalytic effect between the doped Si atoms and the Fe metal atom.
Flavonoids are known for its mechanism of antioxidant property which can prevent DNA damage. These natural products' anticancer and antiviral properties are linked to their mechanism of action. Various examinations reveals that, there will be a adjacent relationship between the molecular structure and their physicochemical properties such as boiling point, melting point, entropy, and so forth. In this work we have presented the physicochemical analysis and determination of -electron energy for some bio-molecular structures namely Erythroxylum Flavonoids, DNA (deoxyribonuclic acid), and RNA (ribonuclic acid). Additionally, the QSPR analysis of bio-molecular structures using ten degree based topological indices are discussed to assist researchers in understanding the chemical reactions and physical properties related with them. Furthermore, we demonstrated that the indices values correlate well with the physicochemical properties of flavonoids, DNA, and RNA molecular structures from the presented regression model.
Lead halide perovskites have been replaced by the environmentally acceptable and effective lead-free double perovskite material. Double perovskites are innovative compounds for sustainable energy and budding substitutes to organic as well as lead-based solar cells. In the current study, it has been expounded on the structural, electronic, thermoelectric, as well as thermodynamic characteristics of newly designed double perovskites In2TiX6 (X = Br, I) by means of ab-initio computations relied on the FP-LAPW tactics and semi-classical Boltzmann transport theory with PBE-GGA as exchange correlation potential. To obtain accurate value of band gaps (1.294 eV and 1.025 eV), TB-mBJ approximation has been used along with PBE-GGA. The best combinations of both compounds have spectroscopic limited maximum efficiency (SLME) values 33.96% and 31.63%, that are appropriate for solar cell absorbers, at 300 K, respectively. We have also computed Debye temperature and Grüneisen parameter to find the lattice thermal conductivity for both the investigated alloys. Thermoelectric properties have been labeled by Seebeck coefficient, electrical as well as thermal conductivities, and figure of merit. The peak values of Seebeck coefficient of 248 μV/K and 202 μV/K are observed for In2TiBr6 and In2TiI6 respectively in the p-type regions. Attained results illustrates that the investigated In2TiX6 may be contender in thermoelectric due to their high figure of merit in low as moderate temperatures. Our results suggest that these materials are viable for use in thermoelectric devices.
Using ab-initio DFT based simulations, the hydrogen storage capacity of transition metal (TM = Ni, Pd) decorated doped germanium carbide nanotubes (GeCNTs) with heteroatoms (B, N, Ga, and As) has been examined. The study reveals that each Ni atom bonded on GeCB, GeCN, GeCGa, and GeCAs can attach at the most of 3H2, 2H2, 4H2, and 5H2 molecules with an average binding energy of −.36, −.40, −.32, and −.37 eV/H2, respectively. When doped GeCNTs are fully decorated with Ni atoms, their gravimetric hydrogen storage capacities are around 4.05, 2.73, 5.38, and 6.57 wt%, respectively. The desorption temperature of the systems is 460, 511, 404, and 473 K, respectively. When doped GeCNTs are fully decorated with Pd atoms, their gravimetric hydrogen storage capacities are around 2.07, 3.07, 4.05, and 3.07 wt%, respectively. These findings demonstrate that doped-GeC adorned with Pd does not satisfy US DOE hydrogen storage requirements. The molecular dynamic (MD) calculations are utilized to examine the stability of the considered structures. The results demonstrate that Ni-adorned GeCAs are a suitable material for hydrogen storage, which will motivate scientists to fabricate GeCAs-based fuel cell devices.
An accurate and computationally efficient determination of the cross sections for electron collision ionization of molecules has various applications, such as plasma physics and atmospheric science. In the case of large molecules, ab initio calculations are often difficult and time-consuming. Here, we develop a feed forward neural network to predict the electron impact ionization cross sections of complex molecules. The training (predicting) set in the method consists of a series of theoretical ionization cross sections for small (large) molecules obtained from the combined model, which integrates the Binary-Encounter-Bethe and Deutsch-Märk models. Several complex systems or targets involving electron collision ionization are evaluated, including molecules such as CH, CH, CH, CH
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：