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Atrazine is a widely used toxic herbicide that poses a threat to both the environment and human health. This study investigates the removal of Atrazine from water through armchair-hexagonal hexagonal graphene quantum dots (AHEX) simulations. The investigations are performed using density functional theory at the exchange–correlation hybrid functional B3LYP/3-21G level of theory. The activity of pristine AHEX, with a total dipole moment of 0.0 (debye), is enhanced by doping with boron (B), nitrogen (N), and sulfur atoms (S), resulting in increased total dipole moments of 8.99, 5.29, and 4.14 Debye respectively. This enhancement occurs without any structural deformation due to the doping process. Our results show significant adsorption capacity of the doped nanographene for Atrazine, evidenced by the high adsorption energies of 0.52 eV for boron, 0.62 eV for nitrogen, and 2.97 eV for sulfur. Charge distribution on the atrazine complexes further confirms effective interaction, with values of 0.03, − 0.018, and 0.032 (e). UV–vis spectroscopy reveals that the prominent absorption peaks of boron and nitrogen-doped samples, initially at ~ 658.8 and 431 nm, undergo a redshift to ~ 676 and 444.3 nm after adsorption, respectively. This redshift aligns with the dominant excitation moving to lower energies following adsorption. Conversely, the sulfurated nanographene shows a blue shift from 980.66 to 485.41 nm. These findings highlight the potential of doped nanographene as an effective treatment for atrazine-contaminated water. [ABSTRACT FROM AUTHOR]

Keeping recruitment of green and cost-effective solutions for environmental challenges in view, the current work was designed to solve the problems related to metal corrosion in the aqueous phases of crude oil in chemical industries. Green materials can play an important role in protecting metals from this corrosion. Hence, the green anti-corrosion material based upon gossypol derivate is suggested to solve the above problems. The electrochemical characteristics were appraised by cyclic voltammetry, electrochemical impedance spectroscopy, potentiodynamic polarization, and electrochemical noise methods. The thermodynamics were studied by gravimetric analyses. The surface morphology was scrutinized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Density functional theory and molecular dynamic simulations were exploited in theoretical analyses. The gossypol derivate is green, non-toxic, more efficient, non-volatile, and chemically stable anti-corrosion material for gas and oil industries. Carbon steel corrosion simulated in aqueous phases of crude oil (NaCl solutions (1.0 M) saturated with H2S and CO2) was maximally prohibited by forming a protective layer of binaphthalene. Its protection degree is 96.71% (at 100.0 mg/L/0.107 mM). The gossypol ring is a suitable core for preparing the next modification materials to protect against corrosion. The rigid adsorption progressed mainly via hydroxyl functional moieties. Compared to the inhibition behavior of the neutral form of gossypol, the optimized protonated form causes a greater inhibition. A gossypol derivate showed excellent anti-corrosive efficiency as a green inhibitor. [ABSTRACT FROM AUTHOR]

The microscopic reaction pathway plays a crucial role in determining the electrochemical performance. However, artificially manipulating the reaction pathway still faces considerable challenges. In this study, we focus on the classical acidic water oxidation based on RuO2 catalysts, which currently face the issues of low activity and poor stability. As a proof-of-concept, we propose a strategy to create local structural symmetry but oxidation-state asymmetric Mn4-δ-O-Ru4+δ active sites by introducing Mn atoms into RuO2 host, thereby switching the reaction pathway from traditional adsorbate evolution mechanism to oxide path mechanism. Through advanced operando synchrotron spectroscopies and density functional theory calculations, we demonstrate the synergistic effect of dual-active metal sites in asymmetric Mn4-δ-O-Ru4+δ microstructure in optimizing the adsorption energy and rate-determining step barrier via an oxide path mechanism. This study highlights the importance of engineering reaction pathways and provides an alternative strategy for promoting acidic water oxidation. Microscopic reaction pathways are crucial for electrochemical performance, but manipulating them remains challenging. Here, the authors report an approach that involves integrating Mn into RuO2 catalysts to switch the reaction mechanism of the oxygen evolution reaction from a traditional single metal-site adsorbate evolution mechanism to a different dual-metal-site oxide path mechanism. [ABSTRACT FROM AUTHOR]

Doping of a Mott insulator gives rise to a wide variety of exotic emergent states, from high-temperature superconductivity to charge, spin, and orbital orders. The physics underpinning their evolution is, however, poorly understood. A major challenge is the chemical complexity associated with traditional routes to doping. Here, we study the Mott insulating CrO2 layer of the delafossite PdCrO2, where an intrinsic polar catastrophe provides a clean route to doping of the surface. From scanning tunnelling microscopy and angle-resolved photoemission, we find that the surface stays insulating accompanied by a short-range ordered state. From density functional theory, we demonstrate how the formation of charge disproportionation results in an insulating ground state of the surface that is disparate from the hidden Mott insulator in the bulk. We demonstrate that voltage pulses induce local modifications to this state which relax over tens of minutes, pointing to a glassy nature of the charge order. Metallic surface states on CoO2 and Pd terminated surfaces due to electronic reconstruction have been observed in the CoO2-based delafossites. In contrast, here the authors report an interesting insulating state on the CrO2 terminated surface of PdCrO2 due to charge-disproportionation. [ABSTRACT FROM AUTHOR]

Emergent phases often appear when the electronic kinetic energy is comparable to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional kagome lattice, including magnetic order, time-reversal symmetry breaking charge order, nematicity, and superconductivity. However, the interlayer coupling of the kagome layers disrupts the destructive interference needed to completely quench the kinetic energy. Here we demonstrate that an interwoven kagome network—a pyrochlore lattice—can host a three dimensional (3D) localization of electron wavefunctions. Meanwhile, the nonsymmorphic symmetry of the pyrochlore lattice guarantees all band crossings at the Brillouin zone X point to be 3D gapless Dirac points, which was predicted theoretically but never yet observed experimentally. Through a combination of angle-resolved photoemission spectroscopy, fundamental lattice model and density functional theory calculations, we investigate the novel electronic structure of a Laves phase superconductor with a pyrochlore sublattice, CeRu2. We observe evidence of flat bands originating from the Ce 4f orbitals as well as flat bands from the 3D destructive interference of the Ru 4d orbitals. We further observe the nonsymmorphic symmetry-protected 3D gapless Dirac cone at the X point. Our work establishes the pyrochlore structure as a promising lattice platform to realize and tune novel emergent phases intertwining topology and many-body interactions. [ABSTRACT FROM AUTHOR]

Here, using first-principles density functional theory (DFT), we investigated the structure cubic calculations of perovskite RbTaO3: bulk and surface (1 0 0). The Ta and O atoms in the TaO2-(1 0 0) termination appear to have a large atomic displacement (ΔZ) for the top and ninth layers, while the Rb atoms appear to have a minor value of ΔZ. In the RbO-(1 0 0), the Rb and O atoms in the first layer appear to have a large ΔZ, while the Ta atoms appear to have a major value of ΔZ in the second and eighth layers. We describe the thermodynamic formality used to evaluate the stability of RbTaO3 bulk, as well as RbO and TaO2-terminations. Our calculations showed that both the bulk system and the terminations are stable with the surrounding O atoms. The RbTaO3 bulk system appears to have semiconducting behavior with a band gap (Eg) of 2.25 eV. New RbO- and TaO2-terminations appeared half-metallic ferromagnetic (HMF) with a spin magnetic moment of 1.00 μβ. We found the Eg for RbO- and TaO2-terminations to be 2.25 and 2.40 eV, respectively. Also, the atomic populations (Q) and the variation (ΔQ) for (1 0 0)-RbTaO3 terminations were analyzed and compared with the bulk system. We calculated the optical properties of the RbTaO3 alloy and RbO- and TaO2-(1 0 0) surfaces. We found weak reflectivity, excellent optical conductivity, and higher absorption of incident energetic photons. Depending on the above properties, it is possible to use the bulk, RbO and TaO2 terminations in spintronics and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Although GaP, a III-V compound semiconductor, has been extensively utilized in the optoelectronic industry for decades as a traditional material, the inherent indirect bandgap nature of GaP limits its efficiency. Here, we demonstrate an indirect-to-direct bandgap transition of GaP through the formation of quantum shells on the surface of ZnS nanocrystals. The ZnS/GaP quantum shell with a reverse-type I heterojunction, consisting of a monolayer-thin GaP shell grown atop a ZnS core, exhibits a record-high photoluminescence quantum yield of 45.4% in the violet emission range (wavelength = 409 nm), validating its direct bandgap nature. Density functional theory calculations further reveal that ZnS nanocrystals, as the growth platform for GaP quantum shells, play a crucial role in the direct bandgap formation through hybridization of electronic states with GaP. These findings suggest potential for achieving direct bandgaps in compounds that are constrained by their inherent indirect energy gaps, offering a strategy for tailoring energy structures to significantly improve efficiencies in optoelectronics and photovoltaics. The indirect bandgap in GaP semiconductors limits its efficiency in optoelectronic applications. Here the authors realize a direct bandgap by forming ultrathin GaP quantum shells on ZnS nanocrystals, greatly enhancing luminescence efficiency. [ABSTRACT FROM AUTHOR]

Thallium, a highly toxic pollutant, shows greater toxicity to human than other common heavy metals such as mercury, lead, cadmium and its effective removal from wastewater gains great attention. The main restriction for the Tl+ removal is the interference of a high concentration of co-existing ions in wastewater. Therefore, the goal of the current work was to synthesis adsorbent with high selectivity for the Tl+ removal. Herein, the pore size sieving strategy was proposed and Prussian blue-impregnated biochar (BC@PB) particles was synthesized. More than 95% Tl+ can be removed even the concentrations of the coexistence ions (Na+, Cd2+, and Zn2+) 1,000 higher than the initial concentration of Tl+ (500 μg/L). BC@PB also showed large adsorption capacity (9365 μg/g) and more than 99% Tl+ (initial concentration, 500 μg/L) were removed in just 1 min. The BC@PB had excellent and stable Tl+ removal ability (> 99%) over a range of pH from 3 to 9, which covered the pH range of common thallium-containing wastewater. The density functional theory (DFT) calculation confirmed that not only hydrated volume but also the hydration free energy of ions, which governed the energy barrier for ions entering into narrow channels of BC@PB, played essential roles on the selectivity removal of Tl+. Overall, due to its high selectivity, high adsorption capacity and easy preparation process, the synthesized BC@PB particles based on the pore sizing sieving strategy, can be a promising candidate for the removal of thallium from wastewater. [ABSTRACT FROM AUTHOR]

Non-fullerene organic compounds are promising materials for advanced photovoltaic devices. The photovoltaic and electronic properties of the derivatives (TTBR and TTB1-TTB6) were determined by employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) analyses using the M06/6-311G(d,p) functional. To enhance the effectiveness of fullerene-free organic photovoltaic cells, modifications were applied to end-capped acceptors by using strong electron-withdrawing moieties. The structural tailoring showed a significant electronic impact for HOMO and LUMO for all chromophores, resulting in decreased band gaps (3.184–2.540 eV). Interestingly, all the designed derivatives exhibited broader absorption spectra in the range of 486.365–605.895 nm in dichloromethane solvent. Among all derivatives, TTB5 was observed to be the promising candidate because of its lowest energy gap (2.54 eV) and binding energy (0.494 eV) values, along with the bathochromic shift (605.895 nm). These chromophores having an A–π–A framework might be considered promising materials for efficient organic cells. [ABSTRACT FROM AUTHOR]

Si and its oxides have been extensively explored in theoretical research due to their technological importance. Simultaneously describing interatomic interactions within both Si and SiO2 without the use of ab initio methods is considered challenging, given the charge transfers involved. Herein, this challenge is overcome by developing a unified machine learning interatomic potentials describing the Si/SiO2/O system, based on the moment tensor potential (MTP) framework. This MTP is trained using a comprehensive database generated using density functional theory simulations, encompassing diverse crystal structures, point defects, extended defects, and disordered structure. Extensive testing of the MTP is performed, indicating it can describe static and dynamic features of very diverse Si, O, and SiO2 atomic structures with a degree of fidelity approaching that of DFT. [ABSTRACT FROM AUTHOR]

Owing to their exceptional mechanical, electronic, and phononic transport properties, compositionally complex alloys, including high-entropy alloys, represent an important class of materials. However, the interplay between chemical disorder and electronic correlations, and its influence on electronic structure-derived properties, remains largely unexplored. This is addressed for the archetypal CrMnFeCoNi alloy using resonant and valence band photoemission spectroscopy, electrical resistivity, and optical conductivity measurements, complemented by linear response calculations based on density functional theory. Utilizing dynamical mean-field theory, correlation signatures and damping in the spectra are identified, highlighting the significance of many-body effects, particularly in states distant from the Fermi edge. Electronic transport remains dominated by disorder and potentially short-range order, especially at low temperatures, while visible-spectrum optical conductivity and high-temperature transport are influenced by short quasiparticle lifetimes. These findings improve our understanding of element-specific electronic correlations in compositionally complex alloys and facilitate the development of advanced materials with tailored electronic properties. Compositionally complex alloys have attracted significant attention recently, but the role of electronic correlations in these materials is unknown. Redka et al. study the CrMnFeCoNi alloy using a combination of experimental and theoretical techniques, revealing strong correlation effects far from the Fermi edge. [ABSTRACT FROM AUTHOR]

The efficient purification of cyclohexane is critical, serving as an essential feedstock to produce resins, nylon fibers and pharmaceutical intermediates. However, efficient purification remains a challenging task due to the similarity of cyclohexane and benzene molecules in terms of size and boiling point. In this work, we reported on the synergy of pore size and silanols inside an -SVR-type zeolite for the efficient production of ultrapure cyclohexane (benzene <1 ppm) from benzene/cyclohexane mixture. Under ambient conditions, the SSZ-74 zeolite demonstrated the highest mass-based productivity of 14.5 L/kg for ultrapure cyclohexane among several common zeolites with a considerable dynamic selectivity of ~9.5. The separation ability was evaluated through density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The unique ordered silanols inside the zeolite frameworks demonstrated strong but reversible interactions with benzene through SiOH...π interactions, as revealed by in situ Fourier Transform infrared (FTIR) spectra. Purification of cyclohexane serves as a feedstock to produce resins, nylon fibers and pharmaceutical intermediates. Here authors combine specific pore sizes with silanols within a zeolite framework to improve the separation of cyclohexane from benzene, addressing the challenge of their molecular size similarity. [ABSTRACT FROM AUTHOR]

Atomistic simulations are crucial for predicting material properties and understanding phase stability, essential for materials selection and development. However, the high computational cost of density functional theory calculations challenges the design of materials with complex structures and composition. This study introduces new data acquisition strategies using Bayesian-Gaussian optimization that efficiently integrate the geometry of the convex hull to optimize the yield of batch experiments. We developed uncertainty-based acquisition functions to prioritize the computation tasks of configurations of multi-component alloys, enhancing our ability to identify the ground-state line. Our methods were validated across diverse materials systems including Co-Ni alloys, Zr-O compounds, Ni-Al-Cr ternary alloys, and a planar defect system in intermetallic (Ni1−x, Cox)3Al. Compared to traditional genetic algorithms, our strategies reduce training parameters and user interaction, cutting the number of experiments needed to accurately determine the ground-state line by over 30%. These approaches can be expanded to multi-component systems and integrated with cost functions to further optimize experimental designs. [ABSTRACT FROM AUTHOR]

We report a novel deep learning (DL) method for classifying inorganic compounds using 3D electron density data. We transform Density Functional Theory (DFT)-derived CHGCAR files from the Materials Project (MP) and experimental data from the Inorganic Crystal Structure Database (ICSD) into point clouds and sparse tensors, optimized for use in DL models such as PointNet and Sparse 3D CNN. This approach effectively overcomes the limitations of handling the dense 3D data, a common challenge in DL. Contrasting with traditional 1D or 2D X-ray diffraction (XRD) patterns that necessitate complex reciprocal space analysis, our method utilizes 3D density data for direct interpretation in real lattice space. This shift significantly enhances classification accuracy, outperforming traditional XRD-driven DL methods. We achieve accuracies of 97.28%, 90.77%, and 90.10% for crystal system, extinction group, and space group classifications, respectively. Our 3D electron density-based DL approach not only showcases improved accuracy but also contributes a more intuitive and effective framework for materials discovery. [ABSTRACT FROM AUTHOR]

Charge density waves (CDWs) in transition metal dichalcogenides are the subject of growing scientific interest due to their rich interplay with exotic phases of matter and their potential technological applications. Here, using density functional theory with advanced meta-generalized gradient approximations (meta-GGAs) and linear response time-dependent density functional theory (TDDFT) with state-of-the-art exchange-correlation kernels, we investigate the electronic, vibrational, and optical properties in 1T-TiSe2 with and without CDW. In both bulk and monolayer TiSe2, the electronic bands and phonon dispersions in either normal or CDW (semiconducting) phase are described well via meta-GGAs, which separate the valence and conduction bands just as HSE06 does but with significantly more computational feasibility. The experimentally observed humps of electron energy loss spectroscopy are successfully reproduced in TDDFT. Our work opens the door to simulating these complexities in CDW compounds from first principles by revealing meta-GGAs as an accurate low-cost alternative to HSE06. [ABSTRACT FROM AUTHOR]

Air pollutants generated from volatile toxic chemicals pose significant public health concerns. Density functional theory (DFT) computations were used in this research to explore the efficiency and mechanism of harmful gas sensing over the reduced graphene oxide-polypyrrole (rGO-PPy) composite. Volatile molecule sensing was investigated for the NH3, H2CO, CH3OH, and C2H5OH gas molecules over three PPy orientations on the rGO substrate. Results showed that PPy orientation over rGO plays a crucial role in the sensing efficiency of the investigated gas molecules. The rGO-PPy composite, with PPy in a vertical orientation, demonstrated higher stability and enhanced sensing than other orientations. The results indicate that the strong hydrogen bonding of NH3 and CH3OH with both PPy and rGO significantly enhanced the sensing of these gas molecules on rGO by influencing the charge transfer with adsorption energy values of − 0.84 and − 0.92 eV, respectively. The lack of a direct hydrogen bonding with rGO and the weak hydrogen bonding with PPy caused a weak adsorption of H2CO and C2H5OH over rGO as indicated by the adsorption energy values of − 0.60 and − 0.78 eV, respectively. Selectivity analysis for the NH3 and C2H5OH gas molecules showed that NH3 can maintain hydrogen bonding with PPy in the presence of C2H5OH while C2H5OH cannot sustain this interaction. This study highlights the importance of the structural and electronic properties of the rGO-PPy composite in volatile pollutant sensing, providing insights for designing high-performance gas sensors. [ABSTRACT FROM AUTHOR]

In the present study, the inhibition performance of some medicinal plants (i.e. Yarrow, Wormwood, Maurorum, Marjoram, and Ribes rubrum) was theoretically and experimentally investigated for mild steel immersed in 1M HCl. In this way, the obtained extracts characterized by Fourier transform infrared spectroscopy (FT-IR) and the electrochemical and theoretical techniques were used to study the inhibition mechanisms of the extracts for the immersed electrode in the acidic solution. In addition, the microstructure of the electrode surface immersed in the blank and inhibitor-containing solutions characterized by field emission scanning electron microscopy (FE-SEM), and Violet-visible (UV–Vis) spectroscopy was used to confirm the adsorption of the compounds on the electrode surface. The obtained electrochemical results revealed that the inhibition performance of the green inhibitors increased by increasing their dosage in the electrolyte. In addition, it was proved that Marjoram plant extract possessed the most inhibition efficiency (up to 92%) among the under-studied herbal extracts. Marjoram extract behaved as a mixed-type inhibitor in the hydrochloric acid solution, and the adsorption process of the extract on the steel surface followed the Langmuir adsorption model. Adsorption of the compounds on the steel surface was also studied using density functional theory (DFT), and it was found that the protonated organic compounds in the extract have a high affinity for adsorption on the electrode surface in the acidic solution. [ABSTRACT FROM AUTHOR]

The substitution of heteroatoms and the functionalisation of molecules are established strategies in chemical synthesis. They target the precise tuning of the electronic properties of hydrocarbon molecules to improve their performance in various applications and increase their versatility. Modifications to the molecular structure often lead to simultaneous changes in the morphology such as different crystal structures. These changes can have a stronger and unpredictable impact on the targeted property. The complex relationships between substitution/functionalization in chemical synthesis and the resulting modifications of properties in thin films or crystals are difficult to predict and remain elusive. Here we address these effects for charge carrier transport in organic crystals by combining simulations of carrier mobilities with crystal structure prediction based on density functional theory and density functional tight binding theory. This enables the prediction of carrier mobilities based solely on the molecular structure and allows for the investigation of chemical modifications prior to synthesis and characterisation. Studying nine specific molecules with tetracene and rubrene as reference compounds along with their combined modifications of the molecular cores and additional functionalisations, we unveil systematic trends for the carrier mobilities of their polymorphs. The positive effect of phenyl groups that is responsible for the marked differences between tetracene and rubrene can be transferred to other small molecules such as NDT and NBT leading to a mobility increase by large factors of about five. [ABSTRACT FROM AUTHOR]

Despite the pivotal role of stannum doping in achieving ultrahigh piezoelectric performance in barium titanate-based ceramics, the fundamental mechanisms underlying this enhancement remain elusive. Here, we introduce a single variable nonstoichiometric stannum strategy in lead-free barium titanate-based ceramics with giant piezoelectricity, revealing that stannum doping contributes intrinsically and extrinsically to enhance piezoelectricity. Density functional theory calculations elucidate the intrinsic enhancement of polarization arising from lattice distortion and increased space for titanium-oxygen bonds induced by optimal stannum doping, which is corroborated by Rayleigh analysis. A phase transition from ferroelectric multiphase coexistence to paraelectric phase is observed, alongside a rapid miniaturized and eventually disappeared domains with increasing stannum doping. This evolution in phase structure and domain configuration induces a nearly vanishing polarization anisotropy and low domain wall energy, facilitating easy polarization rotation and domain wall motion, thereby significantly contributing to the extrinsic piezoelectric response. Consequently, the origins of ultrahigh performance can be attributed to the synergistic effect of stannum-induced intrinsic and extrinsic contributions in barium titanate-based ceramics. This study provides fundamental insights into the role of doping elements and offers guidance for the design of high-performance piezoelectrics. The mechanisms of the enhancement of stannum doping in achieving high piezoelectric performance in barium titanate-based ferroelectric ceramics remain elusive. Here, the authors introduce a single variable nonstoichiometric stannum strategy to reveal the intrinsic and extrinsic contributions for enhancing piezoelectricity after stannum doping. [ABSTRACT FROM AUTHOR]

This article comprehensively investigates the electronic structure and optical properties of InSe/ZnSe vertical van der Waals heterostructures (vdWHs) under biaxial strain modulation and external electric field by using the first-principles calculations based on density functional theory (DFT). Notably, we find the tunability of band gap and electronic performance under biaxial strain and external electric field, as well as the transition from semiconductor to metal. Compared with the single monolayer, InSe/ZnSe vdWHs enhances the light absorption ability, the tensile strain causes the redshift of the optical absorption spectrum of the heterostructure; while the compressive strain enhances the light absorption ability of the InSe/ZnSe vdWHs e in the ultraviolet light region, the external electric field enhances the light absorption ability of InSe/ZnSe vdWHs in the visible light region. The phonon spectrum and elastic constants confirm the dynamic and mechanical stability of InSe/ZnSe vdWHs, proving that it not only exists in theory, but also has the hope of being manufactured in the laboratory. This study provides a theoretical basis for the potential applications of InSe/ZnSe vdWHs in optoelectronic devices and strain-sensitive technologies. [ABSTRACT FROM AUTHOR]

Ab initio calculations based on density functional theory with the PBEsol method were utilized to examine the influence of hydrogen passivation, vacancies, and dopants on the electronic and magnetic properties of zigzag MgO nanoribbons with a width of w = 6 (6Z-MgONR). Calculations suggested that the 6Z-MgONR–2H configuration, which lacked magnetism and exhibited metallic characteristics, was the most stable configuration. Herein, this configuration with intrinsic defects and impurities were deeply considered. Finds revealed that individual VMg and VO vacancies induced magnetic moments of 0.624 μB and 0 μB, respectively. The calculated formation energy indicated that the occurrence of a single VMg was energetically favored than a single VO. Moreover, the three oxygen atoms adjacent to vacancy displayed inconsistent spin polarization directions, resulting in smaller magnetic moments than bulk MgO. Upon the introduction of Li or N impurities, LiMg under O-rich conditions exhibited the lowest formation energy. This was accompanied by an increase in total magnetic moments to 1.435 μB, which was significantly higher in the case of Mg vacancy. The corresponding spin-resolved charge density clearly demonstrated that the spin polarization was strongly localized at the right edge passivation of H atoms, with a minor contribution from the O atoms closest to the right edge H atoms. The NO/6Z-MgONR–2H configuration also exhibited total magnetic moments of 1.872 μB, but it had a substantially higher defect formation energy compared to the LiMg/6Z-MgONR–2H system. [ABSTRACT FROM AUTHOR]

How to induce magnetism for two-dimensional materials has always been a focus of research in nanomaterials science. In this work, employing density functional theory, we investigated the structural stability and electronic-magnetic properties of antimonene-phosphorene (SbP) nanoribbons doped with B, C, N, and O atoms. Additionally, we investigated the effects of vacancy defects along with impurity atoms doping on antimonene-phosphorene nanoribbons. Our analysis revealed that all doped and defected structures displayed robust structural stability, as evidenced by negative binding and formation energies. It was found that the substitution of impurity atoms in either P or Sb positions of the SbP nanoribbon leads to different behaviors, and only the SbP nanoribbons doped with C atom in P position and doped with O atom in Sb position show magnetic properties. Moreover, we observed that the magnetic properties of vacancy structures doped with impurity atoms varied based on the number of doping atoms in P or Sb positions. For instance, spin polarization behavior can be realized in P-vacancy nanoribbons doped with one and two N atoms, and the magnetic moment variations in Sb-vacancy nanoribbon doped with N atoms are nearly three times greater than those of the P-vacancy nanoribbon. Furthermore, the effects of the transverse electric field have also been calculated, and we found that applying an electric field to the system can reduce the band gap and modulate the magnetic moment. Intriguingly, we observed negative differential resistance behavior and an 80% spin filtering effect in antimonene-phosphorene nanoribbons with a phosphorus vacancy. Overall, these findings offer new insights into designing next-generation nano spintronic devices within antimonene-phosphorene nanoribbons. [ABSTRACT FROM AUTHOR]

Enhancing the rate performance of lithium-ion batteries (LIBs) is crucial to developing electronic devices. In light of the growing demand for consumer electronics, researchers have developed two-dimensional (2D) materials to achieve elevated performance levels. In this study, we applied the density functional theory (DFT) approach to assess the suitability of the novel 2D triphosphide AsP3 as a potential anode candidate for LIBs. The AsP3 monolayer exhibits high cohesive energy, outstanding structural stability, and impressive electronic properties. Our finding demonstrates that the valley site As2 is the optimal adsorption site for the Li atom on the AsP3 monolayer, with a high negative adsorption energy of -2.42 eV and considerable charge transfer. Moreover, the transition in behavior from semiconductor to metallic after the adsorption of Li on the substrate makes the AsP3 appropriate as an anode material of LIBs. Meanwhile, the AsP3 monolayer features a high theoretical storage capacity of around 638.71 mAhg− 1, exceeding that of commercial graphite and numerous other 2D materials. The diffusion barrier energy of the Li atom on the AsP3 monolayer is 0.29 eV, which is quite lower than that of many other 2D materials. This indicates rapid charge and discharge processes and underscores the high performance of the AsP3 monolayer. All these results demonstrate that the AsP3 monolayer could be a promising candidate for anode material in LIBs, paving the way for feature experimental studies in the development of battery technology. [ABSTRACT FROM AUTHOR]

Context: A novel 2D InN/GaN lateral heterostructure (LHT) was simulated by stitching monolayer of 2D InN and monolayer of 2D GaN. The structural stability, electronic structure, and optical properties were systematically investigated using first-principle calculations and by considering the effects of strain. The results indicated that the designed heterostructure has a direct bandgap of 2.26 eV which is further affected by applied biaxial strain. The bandgap of 2D InN/GaN lateral heterostructure decreases with the increase in biaxial strain, and tensile strain triggers a direct-to-indirect energy gap changeover at + 6%. Additionally, under compressive strain, heterostructure remains a direct bandgap semiconductor. Furthermore, the strain significantly affects the optical characteristics of lateral heterostructure. It has been noticed that the first optical absorption peak moves from 2.51 eV (ɛ = − 4%) to 1.40 eV (ɛ = 10%). Therefore, 2D InN/GaN lateral heterostructure provides an approachable way for utilizing in optoelectronic devices through the creation of in-plane lateral heterostructures. Methods: We performed all the computations using a self-consistent method based upon density functional theory. We used the PBEsol functional in the GGA to account for the exchange–correlation effects. We introduced a 10-Å vacuum region in the z-direction to avoid interaction between periodic images. We considered non-negligible weak dispersion correction in the lateral heterostructure using Grimme's DFT-D3 approach. In this study, we also computed the electrical and optical properties employing the local modified Becke-Johnson (lmBJ) exchange potential under meta-GGA functional to obtain more precise results. [ABSTRACT FROM AUTHOR]

Context: This work analyzes the isomerization effects and solvent contributions to the stability, electronic excitations, reactivity, and non-linear optical properties (NLO) of resveratrol molecules within the formalism of the Density Functional Theory. The findings suggest that resveratrol solvatochromism is significantly influenced by solvent polarization. The electronic and free energies (E and G) indicate that trans is the most stable conformer. The system is classified as a strong nucleophile. However, the analysis of the Fukui functions and the Mulliken charges indicate that cis-trans isomerization jointly affects the reactive indices of the carbon and hydrogen atoms. The results also suggest that solvent is relevant to solvatochromism and the NLO response. Both cis and trans conformers present strong π - π ∗ excitations that undergo a visible hypsochromic change when the polarity of the solvent increases. Once the absorption spectra are connected to the first hyperpolarization (β ) by the Oudar and Chemla relation, the hypsochromism of resveratrol is the reason for the drop in the generation of the second harmonic when the ambient polarity decreases. The CAM-B3LYP DFT results suggest that resveratrol is interesting for NLO applications. Depending on the choice of solvent, values ∼ 50 times those observed for urea ( β = 0.34 × 10 - 34 esu), which is a standard NLO material. Methods: The optimized geometries of cis and trans isomers of resveratrol in vacuum were obtained using Density Functional Theory (DFT) with the hybrid exchange-correlation function (CAM-B3LYP) and Pople basis set functions, specifically 6-311++G(d,p). The solvent effect on the geometries of both isomers was included using the polarizable continuum model (PCM) with the same level of QM calculation. Vibrational analysis was conducted to confirm that all optimized geometries correspond to the minimum energy. Various electronic properties, including dipole moments, molecular orbitals, transition energy, dipole polarizabilities, and global reactivity parameters, were calculated using both continuum and discrete solvation models based on the sequential QM/MM methodology. All QM calculations were performed with the Gaussian 09 program and the MC simulations with the DICE program. All NLO analysis was carried out using the Multiwfn code. [ABSTRACT FROM AUTHOR]

Context: Milk has nutrient-rich but thermal sensitive matrix that undergoes varying degrees of Maillard reaction (MR) at heating conditions. The MR mainly occurs between lysine residues (Lys) and lactose composed of glucose (Glc) and galactose (Gal), which are abundantly sourced from dairy products. In the present study, the MRs of Glc and Gal with Lys at the initial and intermediate stages have been investigated theoretically using density functional theory (DFT) to simulate the gaseous and aqueous phases. Reaction mechanisms have been proposed, and relative energy changes of different steps were calculated according to the total mass balance. The calculations reveal that both Nα- and Nε-amine groups of Lys can react with the carbonyl functional group of Glc and Gal with the similar potential energy profiles, and Gal is more reactive than Glc. However, the barrier in Nε-channel is lower than in Nα-channel, indicating a faster reaction rate through the former channel compared with the latter. The 5-hydroxymethyl-2-furfural (HMF) and derivative are formed under 3-deoxysone route in the intermediate stage. The calculation results are helpful for proposing a reasonable MR mechanism and suggesting possible control methods of the MRs. Methods: In this study, different levels of DFT calculations have been conducted to investigate the mechanisms and favorability of generating MR products in Glc-Lys and Gal-Lys models at initial and intermediate stages in the gaseous and aqueous conditions. In order to elucidate the molecular models from the perspectives of chemistry and geometry, DFT calculations were performed by the mean of B3LYP functional at basis sets of 6–311 + + G (d, p) and 6–311 + + G (2df, 2p) with optional solvation settings. To examine the solvation effect, the study further constructed models with solvent H2O and calculated in wB97XD functional with 6–31 + G (d) basis set. All computations were carried out Gaussian 09 suite of quantum chemistry software. [ABSTRACT FROM AUTHOR]

Context: The challenge of activating inert allyl monomers for polymerization has persisted, prompting our proposal of the photo-driven radical mediated [3 + 2] cyclization reaction (PRMC). This innovative approach significantly expedites the homopolymerization of multi-allyl monomers, enabling the synthesis of embolic microspheres for hepatocellular carcinoma interventions. PRMC involves allyl monomers to form allylic radicals and then radicals participating in a cycloaddition reaction with unsaturated olefins as radicalophiles to form cyclopentane-based radical products. While extensively studied in the theoretical and experimental homopolymerization, PRMC's application in copolymerization remains unexplored. To address this knowledge gap, we explored the elementary reaction, selecting allyl methyl ether radicals (AMER) and α,β-unsaturated ketones as radicalophiles for copolymerization investigations by density functional theory (DFT) analysis. We quantified energy differences between ground and excited states of reactants, elucidated frontier molecular orbitals, and assessed thermodynamic data for copolymerization feasibility. We also evaluated the electronic properties of reactants, predicting the reactivity of radicalophiles and the interactions of intermolecular reactions. Additionally, we applied transition state theory and interaction/deformation models and conducted a local orbital analysis to comprehensively study excess electron distribution and gyration radius of cyclic radical product. Our findings offer vital insights into PRMC's potential in copolymerization. This research provides a robust theoretical foundation for practical application, enhancing the polymerization field. Methods: Based on density functional theory (DFT), the calculations were performed at the M06-2X/6–311 + + G(d,p) level in/by Gaussian 16 package. Subsequently, our analytical results apply time-dependent density-functional theory (TD-DFT) and solvent modeling (SMD). Single-point energy calculations determine the driving force behind the radicals' reaction with radicalophiles. Furthermore, we assessed the electrostatic potential (ESP) of the reactants. The results of the calculations were visualized by the Multiwfn 3.6 and VMD 1.9 programs. [ABSTRACT FROM AUTHOR]

Context: The aim of this work is to use first principles calculations to examine the effects of different mechanical strains on the optoelectronic and photocatalytic capabilities of the 2D/2D nanoheterostructure of AlN/GaN. By utilizing the lmBJ (Meta-GGA) and PBEsol (GGA) functional, the bandgap of the nanoheterostructure is calculated and found to be 4.89 eV and 3.24 eV. Simulated 2D AlN/GaN nanoheterostructure exhibits exceptional optical and electronic characteristics under applied biaxial tensile and compressive strains. The band gap changes from 4.89 to 3.77 eV, while the energy gap nature transitions from direct to indirect during tensile strain fluctuations of 0% to 8%. Strain is also found to have a significant effect on the optical absorption peaks. And a 0–8% rise in tensile strain causes the initial absorption peak of the 2D AlN/GaN nanoheterostructure to shift from 4.88 to 4.20 eV, which results in a 14% red shift in photon energy for every 2% change in strain. Furthermore, the optimum bandgap and band edge positions of the 2D AlN/GaN nanoheterostructure enable the water redox process to produce hydrogen and oxygen for wide range of pH. Thus, modification via strain may be an effective method for altering the optical as well as electronic characteristics of a 2D AlN/GaN nanoheterostructure, and this study may pave the way for new applications of this material in optoelectronic devices in the future. Methods: In the current work, density functional theory is used to explore every attribute of the 2D AlN/GaN nanoheterostructure. To characterize the electronic exchange–correlation, we used the PBEsol functional. In order to prevent any interlayer contact between periodicity of images, a vacuum is produced along the z-direction of approximately 10 Å. To increase the precision of bandgap prediction, the electronic and optical characteristics were computed using the meta-GGA lmBJ functional. To account for interlayer van der Waals interactions, nanoheterostructure computations were performed using the DFT-D3 functional. [ABSTRACT FROM AUTHOR]

Context: This study explores the interaction between particles in microplastic semi-coke water slurry at the molecular level using molecular simulation methods, specifically DFT calculations and MD simulations. In addition, the experiment of slurry preparation was carried out to study the viscosity and stability of the slurry. The electrostatic potential analysis shows that the interaction between microplastics and dispersant molecules occurs on atoms with large electronegativity or oxygen-containing functional groups, and the energy gap of frontier molecular orbitals indicated that PVC interacts most easily with the dispersant (0.39 eV), followed by PS (1.08 eV) and PET (3.65 eV). In addition, it is also noted that due to the steric hindrance effect, the adsorption energy was opposite to the DFT calculation results: PET was − 213.338 kcal/mol (NNO) which was highest, followed by PS (− 107.603 kcal/mol, NNO), and PVC (NNO) was lowest which was − 94.808 kcal/mol. And RDF shows similar results, which the probability of water molecules in the PET system was the highest, followed by PS, and finally, PVC. The MD results are consistent with the viscosity and stability characterization results of the slurry which PET has the lowest viscosity of 87.3 mPa·s. Finally, this study provides new ideas for the treatment of microplastics and the improvement of the performance of semi-coke water slurry and reveals the interaction mechanism between microplastics and semi-coke water slurry. Methods: All calculations were performed using Materials Studio (MS) version 2020 software, BIOVIA Corporation. The DFT calculation was carried out through the DMol3 module. The DFT calculations include electron density, electrostatics, orbitals, and population analysis. In DMol3 module, the GGA-PBE function was selected to consider gradient changes in density in the simulated calculation. The DFT-D correction was selected, and all electrons were calculated by DNP for accurate core potentials and the DNP file was 4.4. MD simulation was performed through the Forcite module. MD simulation mainly focuses on relative concentration distribution analysis, radial distribution function, and adsorption energy calculation. All molecular geometry optimizations are performed in the Forcite module. In the molecular dynamic part, all simulations used PCFF forcefield. The NVT ensemble was adopted and using the Nosé thermostat. [ABSTRACT FROM AUTHOR]

Context: The study of platinum (Pt) clusters and nanoparticles is essential due to their extensive range of potential technological applications, particularly in catalysis. The electronic properties that yield optimal catalytic performance at the nanoscale are significantly influenced by the size and structure of Pt clusters. This research aimed to identify the lowest-energy conformers for Pt 18 , Pt 19 , and Pt 20 species using Density Functional Theory (DFT). We discovered new low-symmetry conformers for Pt 19 and Pt 20 , which are 3.0 and 1.0 kcal/mol more stable, respectively, than previously reported structures. Our study highlights the importance of using density functional approximations that incorporate moderate levels of exact Hartree-Fock exchange, alongside basis sets of at least quadruple-zeta quality. The resulting structures are asymmetric with varying active sites, as evidenced by sigma hole analysis on the electrostatic potential surface. This suggests a potential correlation between electronic structure and catalytic properties, warranting further investigation. Methods: An equivariant graph neural network interatomic potential (NequIP) within the Atomic Simulation Environment suite (ASE) was used to provide initial geometries of the aggregates under study. DFT calculations were performed with the ORCA 5 package, using functional approximations that included Generalized Gradient Approximation (PBE), meta-GGA (TPSS, M06-L), hybrid (PBE0, PBEh), meta-GGA hybrid (TPSSh), and range-separated hybrid (ω B97x) functionals. Def2-TZVP and Def2-QZVP as well as members of the cc-pwCVXZ-PP family to check basis set convergence were used. QTAIM calculations were performed using the AIMAll suite. Structures were visualized with the AVOGADRO code. [ABSTRACT FROM AUTHOR]

Context: Analytic exchange-correlation kernel formulations are of the outermost importance for density functional theory (DFT) perturbation calculations. In this paper, the working equation for the exchange-correlation kernel of the generalized gradient approximation (GGA) for perturbation dependent auxiliary functions is derived and discussed in the framework of auxiliary density functional theory (ADFT). The presented new formulation is extended to the unrestricted approach, too. A comprehensive discussion of the implementation of the GGA ADFT kernel, using either the native exchange-correlation functional implementations in deMon2k or the ones from the LibXC library, is given. Calculations with analytic exchange-correlation kernels are compared to their finite difference counterparts. The obtained results are in quantitative agreement. Nevertheless, analytic GGA ADFT kernel implementations show substantial improvement in the computational performance. Similar results are reported for analytic second derivatives of effective core potential (ECP) and model core potential (MCP) matrix elements when compared to their finite difference counterparts in molecular frequency analyses. Method: All calculations are performed in the framework of ADFT as implemented in deMon2k. In the ADFT analytic frequency calculations, auxiliary density perturbation theory was used. The underlying two-center exchange-correlation kernel matrix elements are calculated by numerical integration either with analytic or finite difference kernel expressions. Validation calculations are performed with the VWN and PBE functionals employing DFT-optimized DZVP basis sets in conjunction with automatically generated GEN-A2 auxiliary density function sets. In the (Pt3Cu)n cluster benchmark calculations, the RPBE functional was used. For Pt atoms, the quasi-relativistic LANL2DZ effective core potential with the corresponding valence basis set was employed, whereas for Cu atoms, the all-electron DFT-optimized TZVP basis was applied. The auxiliary density was expanded by the automatically generated GEN-A2* auxiliary function set. We run all benchmark calculations in parallel on 24 cores. [ABSTRACT FROM AUTHOR]

Using nitrogen-doped graphene quantum dots (N-GQDs) and 3-aminophenylboronic acid (APBA), a novel fluorescence nanosensor was developed. This nanosensor exhibits high selectivity and sensitivity for lysine detection. Its sensing mechanism involves the suppression of electron transfer from APBA to the N-GQDs unit, thereby inhibiting photoinduced electron transfer and initiating internal charge transfer. At an optimal pH of 7, the protonated α-amine and ε-amine groups of lysine interact with the amide and boronic acid moieties, respectively. This interaction results in a redshift of fluorescence, substantially enhancing the response signal. A linear response was observed within a concentration range 0.40–3.01 μM, with the detection limit being 0.005 μM. A similar linear range was also achieved for the determination of lysine in human serum. Density functional theory calculations correlating molecular orbits and geometries support UV–vis and fluorescence findings. Additionally, the nanosensor was successfully applied to detect lysine in living cells and real samples, including milk and honey. For practical application, we construct a lysine-specific sensing platform using a commercial chip (TCS34725) that collects red, blue, and green signals, thereby facilitating the convenient use of the nanosensor. Overall, this study offers new perspectives on the development and application of fluorescent nanosensors for detecting individual amino acids. [ABSTRACT FROM AUTHOR]

For the first time the sensitive determination of carbendatim (CRB) is reported utilizing a well-designed sensing architecture based on vanadium diselenide-multiwalled carbon nanotube (VSMC). FTIR, XRD, FESEM, EDS, and EIS were employed to evaluate the sensor's structural integrity, and the results demonstrated the successful integration of nanomaterials, resulting in a robust and sensitive electrochemical sensor. Cyclic voltammetry (CV) and chronoamperometric (CA) investigations showed that the sensor best performed at pH 8.0 (BRB) with an excellent detection limit of 9.80 nM with a wide linear range of 0.1 to 10.0 µM. A more thermodynamically viable oxidation of CRB was observed at the VSMC/GCE, with a shift of 200 mV in peak potential towards the less positive side compared with the unmodified GCE. In addition, the sensor demonstrated facile heterogeneous electron transfer, favorable anti-fouling traits in the presence of a wide range of interferents, good stability, and reproducible analytical performance. Finally, the developed sensor was validated for real-time quantification of CRB from spiked water, food, and bio-samples, which depicted acceptable recoveries (98.6 to 101.5%) with RSD values between 0.35 and 2.23%. Further, to derive the possible sensing mechanism, the valence orbitals projected density of states (PDOS) for C, H, and N atoms of an isolated CRB molecule, VSe2 + CNT and VSe2 + CNT + CRB were calculated using density functional theory (DFT) calculations. The dominant charge transfer from the valence 2p-orbitals of the C and N atoms of CRB to CNT is responsible for the electrochemical sensing of CRB molecules. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a foremost threat to global health, necessitating innovative strategies for discovering antimicrobial agents. This review explores the role and recent advances of in-silico techniques in identifying novel antimicrobial agents and combating AMR giving few briefings of recent case studies of AMR. In-silico techniques, such as homology modeling, virtual screening, molecular docking, pharmacophore modeling, molecular dynamics simulation, density functional theory, integrated machine learning, and artificial intelligence, are systematically reviewed for their utility in discovering antimicrobial agents. These computational methods enable the rapid screening of large compound libraries, prediction of drug-target interactions, and optimization of drug candidates. The review discusses integrating in-silico approaches with traditional experimental methods and highlights their potential to accelerate the discovery of new antimicrobial agents. Furthermore, it emphasizes the significance of interdisciplinary collaboration and data-sharing initiatives in advancing antimicrobial research. Through a comprehensive discussion of the latest developments in in-silico techniques, this review provides valuable insights into the future of antimicrobial research and the fight against AMR. [ABSTRACT FROM AUTHOR]

The emergence of zoonotic monkeypox (MPX) disease, caused by the double-stranded DNA monkeypox virus (MPXV), has become a global threat. Due to unavailability of a specific small molecule drug for MPX, this study investigated Moringa oleifera phytochemicals to find potent and safe inhibitors of DNA Polymerase (DNA Pol), a poxvirus drug target due to its role in the viral life cycle. For that, 146 phytochemicals were screened through drug-likeness and molecular docking analyses. Among these, 136 compounds exhibited drug-like properties, with Gossypetin showing the highest binding affinity (− 7.8 kcal/mol), followed by Riboflavin (− 7.6 kcal/mol) and Ellagic acid (− 7.6 kcal/mol). In comparison, the control drugs Cidofovir and Brincidofovir displayed lower binding affinities, with binding energies of − 6.0 kcal/mol and − 5.1 kcal/mol, respectively. Hydrogen bonds, electrostatic and hydrophobic interactions were the main non-bond interactions between inhibitors and protein active site. The identified compounds were further evaluated using molecular dynamics simulation, density functional theory analysis and ADMET analysis. Molecular dynamics simulations conducted over 200 ns revealed that DNA Pol-Gossypetin complex was not stable, however, Riboflavin and Ellagic acid complexes showed excellent stability indicating them as better DNA Pol inhibitors. The density functional theory analysis exhibited the chemical reactivity of these inhibitor compounds. The ADMET analysis suggested that the top phytochemicals were safe and showed no toxicity. In conclusion, this study has identified Riboflavin and Ellagic acid as potential DNA Pol inhibitors to control MPXV. Further experimental assays and clinical trials are needed to confirm their activity against the disease. [ABSTRACT FROM AUTHOR]

In order to effectively remove Co2+ from radioactive wastewater, β-cyclodextrin/graphene oxide (β-CD/GO) was synthesized. The factors affecting the adsorption of Co2+in water were determined by static adsorption experiments, and the synthesis and adsorption mechanism of the materials were discussed by using Density Functional Theory (DFT). The results show that β-CD and GO are mainly bonded by ester group and hydrogen bond, the adsorption of Co2+ by β-CD/GO belongs to single molecular layer chemisorption, and the intramolecular diffusion is the main factor of affecting the adsorption rate. The adsorption capacity of Co2+ can reach 95.83 mg/g under appropriate conditions, but it will be affected by interference ions. [ABSTRACT FROM AUTHOR]

Among the various Schiff bases, those containing 2,4-diaminotoluene as a primary amine and 2-hydroxy-4-methoxybenzaldehyde as a carbonyl compound are new and deserve special attention because their logical spectral properties find application in analytical chemistry as a smart probe. The new Schiff base has been synthesized to its pure crystalline form. It is characterized by single-crystal XRD, FT-IR, NMR, TGA, and mass spectrometry. We have studied the spectral properties of the Schiff base and its aluminium adduct by UV-vis and fluorescence spectroscopy and rationalized them by computational analysis. The Job's plot and mass spectrometry indicate the 1:1 binding ratio between the ligand and the Al3+ ion. The suitable binding constant value (8.329×103 M–1) leads to the development of Al3+ sensation by the Schiff base. The sensor has an appreciably low limit of detection value of 7.638×10–9(M), i.e., 0.00163 ppm for Al3+. The logical behaviour of the probe (NAND-type molecular logic gate with two inputs, Al3+ and EDTA) leads to the development of a renewable aluminium testing kit. [ABSTRACT FROM AUTHOR]

In this study, we have investigated a strategy for designing some novel pyrazoline-thiazole hybrids containing azo moiety. The synthesized compounds were structurally characterized and their antibacterial activity was in vitro evaluated against gram-negative and gram-positive bacteria using the inhibition zone method. The antibacterial activity of the tested compounds was moderate to good. Compound 12c showed the best activity compared to the standard drug (Ampicillin) against S. aureus and E. coli at the concentration of 0.16 mg/mL, with the highest inhibition zone diameters of 34 mm and 37 mm, respectively. Moreover, in silico molecular docking and ADME profile studies were investigated in order to understand the binding affinity and interactions along with the ADME properties of all designed hybrids. Additionally, Density functional theory (DFT) calculations were carried out at the B3LYP/6-311G++ level of theory. The study involved an examination of the optimized geometry, molecular electrostatic potential map, and the HOMO → LUMO electronic energy gap. In accordance with the findings, the newly synthesized hybrids could be beneficial for medicine and exhibit antibacterial activity. [ABSTRACT FROM AUTHOR]

Modifying electrical and optical properties in two-carbon materials is essential for electronic devices, energy storage and biosensor applications. We report a comparative study of the effect of systematically intercalated strontium atoms in AA- and AB-stacked bilayer graphene (BG) in the framework of density functional theory (DFT). The electronic band structures, the total and partial electronic density of states and the dielectric function are studied. We show that the intercalation of atoms can influence both electronic properties. Our results show that the Dirac cones, a signature of graphene, are translated into the conduction band. This property may be useful in band-gap tuning applications of nanodevices. The optical properties were calculated parallel and perpendicular to the graphene sheet under polarised electric fields. The calculated optical properties show that the intercalation of Sr in the AA- and AB-stacked BGs promotes IR absorption. The findings provide a basis for developing graphene intercalary compounds, which can be used in optoelectronics to control the absorption of light wavelengths and specifically in biosensor applications. [ABSTRACT FROM AUTHOR]

In the present work, we numerically and experimentally study the Co 3 - x Ni x O 4 (spinel-like oxides) system. Using the perturbative density functional theory (p-DFT) method, we start the study from the homogeneous sample ( x = 0 ), obtaining the main electronic properties (band structure (BS), density of states (DOS), and Fermi surface (FS)). Subsequently, we doped (x) with Ni atoms in different proportions (0–7% respectively, taking 56 atoms as 100% and the percentage of doping, on this percentage). As we increase the doping (x ≠ 0) , we have found that the forbidden gap decreases and the Fermi energy (FE) decreases, causing the material to exhibit a transition phase for a particular doping value. In addition, we find that more bands are generated when the system is doped, which would be responsible for the phase transition. The data from the theoretical analysis carried out in this paper was compared with the experimental data of various widely accepted works. Some of the results, when compared with the information available from the experimental ones, show good agreement. [ABSTRACT FROM AUTHOR]

This research investigates the adsorption efficiency of a chitosan-bentonite (Ch–B) composite in removing methyl orange (MO), a common textile dye, from aqueous solutions. The study integrates experimental and theoretical analyses, employing density functional theory (DFT) to gain insights into the molecular interactions between the composite material and MO molecules. The Ch–B composite was characterized using various techniques, including FT-IR spectroscopy, XRD, and SEM–EDX. The experimental results indicate that the Ch–B composite exhibits a high adsorption capacity for MO, with optimal conditions identified for efficient removal. The Langmuir model was found to best fit the experimental data and the adsorption capacity was 117 mg g−1. Adsorption thermodynamics showed that the adsorption process was spontaneous, feasible, and exothermic. DFT calculation results are correlated with experimental findings to confirm theoretical predictions and improve the overall understanding of the adsorption process. Electronic structure calculations reveal the nature of the interactions between the Ch–B composite and MO molecules, including hydrogen bonds and electrostatic forces. [ABSTRACT FROM AUTHOR]

Due to experimental challenges and computational complexities, limited research has explored high-temperature and high-pressure conditions on mineral vibrations. This study employs the quasi-harmonic approximation (QHA) and density functional theory (DFT) to investigate the impact of temperature and pressure on the structural properties and infrared and Raman vibrational modes of forsterite. The computational process involves determining lattice parameters, optimizing the internal crystal structure, and calculating IR and Raman spectra at various temperature and pressure values, both separately and combined. Results highlight significant anisotropy in forsterite, with the b-axis being most sensitive to temperature and pressure, followed by the c-axis, while the a-axis exhibits greater stiffness. The positions of vibrational modes typically shift to higher frequencies with increasing pressure (average shift of 2.70 ± 1.30 cm−1/GPa) or to lower frequencies with increasing temperature (average shift of − 0.017 ± 0.018 cm−1/K). Modes associated with SiO4 stretching and bending are less affected by temperature or pressure than translational and rotational modes. A brief investigation into isotope and chemical substitution, as well as cation distribution, in the solid solution (Mg, Fe)2SiO4 reveals lower wavenumbers in fayalite modes compared to forsterite modes, attributed to the heavier Fe mass and larger cell parameters. This study establishes a methodology for computing vibrational frequencies under simultaneous temperature and pressure and emphasizes the significant impact of various factors on vibrational modes. Caution is advised when using vibrational modes for identifying compositions within solid solutions. [ABSTRACT FROM AUTHOR]

The heat of mixing of some petrological relevant substitutions (i.e., Mg-Al, Si-Al, Mg-Ti, Mg-Ca, and Mg-Fe) was investigated systematically in silicates, titanates, tungstates, carbonates, oxides, hydroxides, and sulphates by density functional theory calculations (e.g., melilite, chlorite, biotite, brucite, cordierite, amphibole, talc, pseudobrookite, pyroxene, olivine, wadsleyite, ilmenite, MgWO4, ringwoodite (spinel), perovskite, pyrope-grossular, magnesite-calcite, MgO-CaO, anhydrous and different hydrated MgSO4). A specific substitution is characterised by different microscopic interaction energies in different minerals, e.g., the octahedral Mg-Al exchange on a single crystallographic site in pyroxene has a microscopic interaction energy that is more than twice compared to that in biotite. A comparative investigation of the heat of mixing using microscopic interaction energies on a single crystallographic site has the advantage that they are not influenced by cation ordering. They could be successfully correlated with the stiffnesses of the minerals, which in turn were scaled to the oxygen packing fraction, a parameter that is easily available for poorly investigated minerals. With this information, the interaction energies of a certain substitution can be transferred from minerals where they are well-known to mineral groups where they are less- or unknown. Using the cross-site terms and the microscopic interaction energies, the macroscopic interaction energies of the coupled substitution, e.g., Mg + Si = Al + Al, of biotite and pyroxene were calculated, which are, however, affected by cation ordering and different degrees of local charge balance, for which appropriate models are necessary. [ABSTRACT FROM AUTHOR]

The π-binding of iron tricarbonyl, Fe(CO)3, tripod is known to effectively alter the stereoselectivity and torquoselectivity of electrocyclic ring opening (ERO) of cyclobutene and its derivatives by changing the mechanism. Representative examples of pseudopericyclic and also borderline pericyclic ERO reactions were chosen for the present study to establish the role of Fe(CO)3 in manipulating the reactions. The parameters like nucleus-independent chemical shift (NICS), natural bond orbital (NBO) analysis, and topological parameters like ∇2ρ(r) (Laplacian) and ε (ellipticity) have revealed marked drifting of the reaction lying on the pseudopericyclic end to the borderline pericyclic end, which is due to Fe(CO)3 binding. Iron tricarbonyl alters the nature of pseudopericyclic reaction by making it borderline pericyclic. Activation barrier increases for pseudopericyclic case which is very low in the absence of Fe(CO)3. No disconnection of orbitals is observed for pseudopericyclic system when complexed with Fe(CO)3. [ABSTRACT FROM AUTHOR]

B3LYP was employed as a density functional to inspect the impact of Mn doping on the ability of graphyne (Gr) in the delivery of the propylthiouracil (PTU) drug. The interaction between the pure Gr and PTU was weak. Doping of the Mn metal into the Gr surface raised the PTU adhesion energy from −6.1 to −28.3 kcal mol−1, and PTU prefers to attach through its O atom to an Mn of the Mn-doped Gr (Mn@Gr). The analysis of partial density-of-states demonstrated that Mn substantially contributes to generating the virtual orbitals of Mn@Gr. It indicates the suitability of Mn, in contrast to the C atoms of Gr, for the nucleophilic attack. In addition to substantial energy release, the electronic properties of Mn@Gr were appreciably sensitive to the attachment of PTU, making it possible for recognizing the trajectory of the drug. A drug release mechanism was provided in cancer tissues, demonstrating that in cancer cells with a low pH, PTU and Mn@Gr were protonated significantly, thus separating PTU from the surface of Gr. Finally, there was a change in the reaction mechanism of PTU with Mn@Gr from covalent bonding in the natural environment to the H-bonding in the acidic environment of cancerous cells. [ABSTRACT FROM AUTHOR]

Spinel oxides are a type of material that can be used in a wide range of applications, such as photocatalysis, hydrogen production and environmental protection. In this respect, calcium aluminate (CaAl2O4) and chromate (CaCr2O4) spinels were synthesized in this study by the coprecipitation method using potash solution as a precipitant. CaAl2O4 and CaCr2O4 spinels were annealed at 900 and 1100°C, respectively, for different periods. The obtained spinels were first characterized by thermal analysis, and the phase composition of the oxides was analysed using X-ray diffraction. Hydroxyl groups and absorbed water in the obtained precipitates disappeared after calcination and were observed via Fourier transform infrared spectroscopy. BET and SEM/EDS analyses were also used to determine the total surface area of the powder particles, the size of the grains and the morphology of the powders of the synthesized nanoparticles, respectively. The structural and morphological analyses revealed the formation of single-phase CaAl2O4 and dual-phase CaCr2O4, with specific surfaces for each spinel of 44.2165 and 5.7190 m2 g−1, respectively. Moreover, DFT calculations were performed on the materials, and the direct bandgaps of these spinels were found to be 4.365 eV for CaAl2O4 and 2.256 eV for CaCr2O4. The results indicated that different compositions led to different optical bandgaps. Finally, the results indicate that due to the suitable characteristics and properties of the produced spinel oxides, they are among the promising materials that may be employed as semiconductors for various applications. [ABSTRACT FROM AUTHOR]

In this research study, the ability of a boron nitride nanocluster (hereafter B24N24 NC) to detect osmium tetroxide (hereafter OT) after the decoration of Ni into the B24N24 is investigated through the density functionals B3LYP, M06-2X and B97D. The results revealed that the interaction of the pure B24N24 was a physical adhesion or adsorption and the sensing response (SR) of B24N24 is approximately 5.2. The adsorption energy of OT becomes more negative by changing from −5.0 to −20.9 kcal mol−1 after the decoration of the Ni metal on the surface of B24N24, which also leads to a noticeable increase in the corresponding SR to 76.2, indicating that the sensitivity of Ni-decorated B24N24 (Ni@B24N24) is increased. Based on energy decomposition analysis, the nature of the interaction between OT and Ni@B24N24 is mostly an electrostatic cation–lone pair interaction. The theoretically obtained results further confirmed that Ni@BN-based nanostructures can be used for practical purposes. [ABSTRACT FROM AUTHOR]

In this study, the optical properties of porous silicon (PSi), such as the dielectric function, absorption coefficient, bandgap, reflectivity and refractive index, were studied as a function of porosities ranging from 3% to about 40% by using a supercell model in an ab-initio pseudo-potential plane wave (PP-PW) method based on density functional theory (DFT). To validate these theoretical results, various PSi samples were prepared by varying the etching parameters to achieve similar porosities. The PSi samples were subjected to UV–vis spectrophotometry in order to measure their reflectivity. The refractive indexes predicted by DFT were compared to those obtained by the Fresnel equation and the effective medium approximation methods (EMA), particularly Bruggeman's, Looyenga's and del Rio's model (dRZW). These studies showed that the PSi dielectric constant decreases with increasing porosity, which is consistent with a decrease in the refractive index. In addition, as the porosity of PSi rises, the bandgap energy values increase, which is closely related to the decrease in the refractive index. For low porosity, DFT and Looyenga refractive indexes fit better than dRZW or Bruggeman. Furthermore, when the porosity is increased, DFT gives similar results as dRZW and is better than the Bruggeman method. Moreover, at medium porosity (28 or 40%), DFT and EMA models agree well with the experimental refractive indexes of PSi. [ABSTRACT FROM AUTHOR]

Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants. In this research, activation reactions of Shenmu coal powder were carried out in a vertical tube furnace. The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H2O to CO2 in the activation atmosphere. The theoretical validation was conducted through density functional calculations. The two gas molecules follow different pathways to increase the reactivity of char. CO2 mainly participates in the cross-linking reaction by intensifying branching, while H2O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups. Gas molecules partially compete for active sites in a mixed gas atmosphere, but there is a synergism between the two effects. The synergism can be attributed to two possibilities. The inclusion of H2O mitigates the generation of five-membered rings to a limited extent, while concurrently enhances the development of oxygen-containing functional groups. Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char, consequently leading to a reduction in the energy demand for subsequent bond cleavage. [ABSTRACT FROM AUTHOR]

α-AlH3 is regarded as one of the most promising hydrogen storage materials due to its high hydrogen storage capacity (10.1 wt.%, 148 kg·m−3). However, in practical applications, the associated hydrogen release temperature remains relatively high. To effectively address this issue, hollow structured Fe@C nanorods derived from Fe-MOF are introduced as highly efficient catalyst to optimize the dehydrogenation properties of α-AlH3. Comparatively, the initial hydrogen release temperature of α-AlH3 + 3 wt.% Fe@C is reduced to 94.2 °C, which is significantly lower than that of pure α-AlH3 (137.8 °C). At 100 and 120 °C, it exhibits hydrogen capacities of 5.38 wt.% and 7.47 wt.%, respectively, whereas pure α-AlH3 only delivers hydrogen capacities of 0.24 wt.% and 5.94 wt.% under the same temperatures. The density functional theory (DFT) calculations further indicate that the existence of Fe@C catalyst can make the length of Al–H bond increase, which is more conducive to the release of hydrogen. The results show that the synergistic effect of Fe and porous carbon in Fe@C nanorods can improve the hydrogen desorption kinetics of α-AlH3, providing a good prospect for the application of α-AlH3 in hydrogen storage fields. [ABSTRACT FROM AUTHOR]