Mulliken Population Analysis Research Articles

Titanium (IV) μ-Oxo Complex Supported by Phenoxyimine Ligand: Synthesis, Crystal Structure Characterisation, DFT and Molecular Docking Studies

Background: Most of the transition elements in the 3d series (first row transition metals) have been discovered to be extremely significant and practical in biological systems. Naturally, many of the enzymes that are present in the human body system act as catalysts for biological processes and are made of coordination compounds or complexes. Objective: The complex has been characterised by various spectroscopic and analytic techniques. A suitable crystal analysed by X-ray diffraction establishes the formation of a stable binuclear µ-oxo-complex with a hexacoordinate titanium centre. Methods: A new crystalline complex [Ti{La}] has been synthesised in the reaction of titanium butoxide with a phenoxyimine ligand in a 1:1 stoichiometry in toluene at room temperature under a nitrogen atmosphere. The newly synthesised Ti complex has undergone density functional theory and docking study. Results: The crystal shows a monoclinic system with space group C 1 2/c 1. X-ray crystal structure analysis reveals that this complex has a rhomboidal Ti-O-Ti core and exhibits a C2 symmetric conformation with distorted octahedral geometry. Density Functional Theory (DFT) calculations giving insights into the frontier orbitals and mulliken charge analysis, which showed good correlation with the experimental findings. Additionally, in silico molecular docking of ligand and complex was carried out against the HER2 inhibitor kinase. Conclusion: This complex exhibits a higher binding energy of ΔGb = -19.7 kcal/mol with the active pocket of HER2 (PDB:7JXH) than the ligand ΔGb = -8.5 kcal/mol.

Analyze and assess the spectral, DFT, and medicinal characteristics through targeted pharmacological investigation of 2-(3-(5-(4-chlorophenyl)furan-2-yl)acryloyl)-3,4-dihydro-2H-naphthalen-1-one (CHFADN)

The compound 2-(3-(5-(4-chlorophenyl)furan-2-yl)acryloyl)-3,4-dihydro-2H-naphthalen-1-one (CHFADN) was synthesized using the Claisen-Schmidt condensation method, reacting aromatic aldehydes with methyl ketones. Characterization was performed using NMR, FTIR, and UV–visible spectroscopy. A theoretical model was developed with Gaussian 09 software, utilizing the B3LYP/6–311++G(d,p) basis set, to investigate geometric, electronic, and spectroscopic properties, including geometry optimization, harmonic vibration simulations, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), and Mulliken's population analysis. A scaling factor of 0.9600 ensured alignment between the compound's vibrational spectrum and the experimental IR spectrum.In-vitro testing showed notable bactericidal efficacy,H2O2 scavenging activity and antidiabetic activity. In silico molecular docking using AutoDock 4.0, focusing on the 1HD2 protein's active pocket, revealed a binding interaction energy of -6.5 kcal/mol. ADME properties were predicted based on retention data (RM0). The compound showed no mutagenic effects in toxicity testing, indicating a promising safety profile for new drug candidates.

Discovery of new molecular hybrid derivatives with coumarin scaffold bearing pyrazole/oxadiazole moieties: Molecular docking, POM analyses, in silico pharmacokinetics and in vitro antimicrobial evaluation with identification of potent antitumor pharmacophore sites

This synthetic organic methodology involves the creation of novel coumarin-based hybrids of series (1–4) with pyrazole ring and (5–8) with oxadiazole moiety. The targeted compounds were tested for In vitro Antimicrobial efficacy against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans pathogenic microbes using disc diffusion and broth microdilution with ciprofloxacin and fluconazole as reference standards. Density functional theory (DFT) studies were used to study atomic structure and reactivity, including absolute electronegativity (χ), electrophilicity (ω), electron acceptor (ω+), donor capabilities (ω–), electron affinity (EA), energy gap (ΔE), global hardness (η), global softness (S), and ionisation potential (IP) and FMOs, NBOs, MEP, and Mulliken Charge analysis. The POM tests found three integrated pharmacophore sites with antibacterial, antiviral, and anticancer activities. Molecular docking studies are also used to determine the S. aureus nucleoside diphosphate kinase receptor’s affinity and mode of action for the synthesized drugs. In silico analysis of thermodynamic and therapeutic effectiveness properties, including Lipinski’s ’rule of five’, Veber’s rule, and ADME properties, predicted toxicity-free, non-carcinogenic, and risk-free oral administration of the synthesized complexes.

Hazard reduction of heavy metals by co-pyrolysis of modified vermiculite with paper mill sludge/municipal solid waste: Characterization, risk and reaction mechanism study in pyrolytic environment

The increasing volume of paper mill sludge (PM) and municipal solid waste (MW) poses environmental problems associated with heavy metals. Co-pyrolysis of PM/MW with additives effectively reduces the risk of heavy metal contamination. In this study, co-modified vermiculite (LMV) was prepared using the modification methods of intercalation-exfoliation, Mg2+ impregnation, and thermal activation. PM and MW were mixed at different doping ratios, and a non-doping experiment was performed to compare the pyrolysis processes and the retention rates for different heavy metals (Zn, Cr, Cu, Cd, and Pb), as well as the potential ecological risks, and the form distribution of the heavy metals. The addition of LMV reduced the risk posed by heavy metals. In the absence of doping, a higher pyrolysis temperature is conducive to an increase in the oxidizable and residual fractions of heavy metals without higher retention rates. Among these heavy metals, Zn, Cr, and Cu had higher retention rates and low risks, whereas Cd had a relatively high risk with low retention rates. Simulations showed that there was a transfer of the Mulliken charge after the reaction, indicating that all the heavy metals can interact with O, Al, and Si in the LMV; this reaction mainly occurs around the No. 17 O atom of the LMV. The monomers, oxides, and chlorides of Zn/Cr/Cu exhibited better adsorption on vermiculite compared to that of Pb/Cd.

Allethrin and tetramethrin molecular adsorption on novel phosphoaluminane nanosheet based on first-principles investigation

Allethrin and tetramethrin are both active ingredients in the production of insect spray. Being very toxic in nature, the inhalation of allethrin and tetramethrin causes various side effects in human beings. For the detection of allethrin and tetramethrin, the effectiveness of the base material phosphoaluminane is studied in the current work with the help of the density functional theory (DFT) calculations. The stability of phosphoaluminane is ensured with the support of formation energy and phonon band spectrum. The electronic properties of phosphoaluminane are systematically investigated using band structure and projected density of states (PDOS) maps. The obtained band gap value of phosphoaluminane is 1.716 eV, which confirms that the base material has semiconducting properties. The adsorption behaviour of target molecules allethrin and tetramethrin on phosphoaluminane are explored with prominent parameters including adsorption energy, Mulliken population analysis, and relative band gap changes. The adsorption energy range is recorded to be in the scope of −0.237 eV to −0.597 eV. From the results, it is clear that both allethrin and tetramethrin are physisorbed on phosphoaluminane sheets. Hence, novel phosphoaluminane nanosheets can be utilised as a sensing material for allethrin and tetramethrin.

Spectroscopic, solvent interactions, topological analysis, docking evaluation with biological studies on 1,3,3-trimethyl-2-oxybicyclo[2.2.2] octane by anti-cancer proteins

In the current study the title molecules have been shown the anticancer properties of few cancers cell line and biological activity. Electron transition, solute solvent, experimental and computational exploring on the natural bio-molecular structure 1,3,3-tri methyl-2-oxybicyclo[2.2.2] octane stimulated by B3LYP/6–311++G (d,p) set. The 1TOBO molecular structure has identified from GC–MS study by extract of Zingiber Officianale Roscoe. The optimized parameters are correlated with XRD data and NBO expressed the delocalization of charge due to intermolecular interactions and their stronger stabilization E(2) = 4.01 Kcal/mol. The experimental spectral data recorded in the range 400–4000 cm−1 of 1TOBO and strong correlated with computational spectral have been estimated. The UV–vis spectra of corresponding gas phase and solvent-liquid estimated by TD-SCT process well agreement with reported spectra. 1H and 13C NMR spectrum have been capturing the chemical shifts of 1TOBO interpreted by Gauge Independent Atomic Orbital (GIAO) approach with carbinol solvent. The HOMO-LUMO values, Mulliken charges and MEP surface were used to predict the regioselectivity reaction in the region of electrophilic and nucleophilic attack. The topological analysis of LOL and ELF surfaces have been estimated and RDG-NCI map exhibits the van der Walls, steric effect and strong hydrogen bond interaction within the molecules. The Electron-hole distribution analysis revealed the electron transition of three excited states. Furthermore, the quantitative analysis of drug likeness and ADMET were studied. The molecular docking determines the lowest binding impact on the 1TOBO against cancer proteins 7QTZ, 1OXR have been estimated by Auto dock software.

Crystal structure, Hirshfeld surface analysis, computational study and molecular docking simulation of 4-aminoantipyrine derivative

Herein, a new derivative (4APSA) has been synthesized by treating 4-aminoantipyrine with succinic anhydride at 25 °C employing glacial acetic acid as a solvent. The molecular structure of 4APSA is investigated via single crystal X-ray diffraction (XRD) analysis. Cambridge structure database CSD 2023.3.1 (updated March 2024) was used for comparison of 4APSA with the associated reported structures. The supramolecular assemblage was alleviated by several intermolecular connections. Hirshfeld surface analysis was conducted for further assessment of intermolecular interactions with respect to interatomic contacts for 4APSA and a closely associated structure having a reference code of HOMDUI. Interaction energy calculations were performed at B3LYP/6–31G(d,p) electron density level to find the type of interaction energy that had the highest contribution to the supramolecular assembly. Moreover, in-depth DFT calculations were studied at B3LYP/6-311++g(d,p) level to obtain molecular structure, Mulliken charge analysis, MEP surface, electronic properties, quantum chemical reactivity, and DOS spectrum. Strong correlations are found between theoretical and experimental structures. The ADME-T prediction was applied for the 4APSA, 4AP, and SA compounds utilizing OSIRIS DataWarrior. Docking simulation demonstrates the high tendency of 4APSA to bind with the active sites of Cannabinoid Receptor Subtype 2 (CB2R) compared to JWH-018. This finding suggested that the synthesized compound has a positive effect on the CB2R protein.

Exploring the molecular solvatochromism, stability, reactivity, and non-linear optical response of resveratrol.

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 excitations that undergo a visible hypsochromic change when the polarity of the solvent increases. Once the absorption spectra are connected to the first hyperpolarization ( ) 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 ( esu), which is a standard NLO material. 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.

A comprehensive investigation on one-pot synthesis of imidazole derivatives: quantum computational analysis, molecular docking, molecular dynamics simulations and antiviral activity against SARS-CoV-2

New derivatives of 4-(2-(2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-4,5-diphenyl-1H-imidazol-1-yl)ethyl)morpholine (DDIM) have been successfully synthesised and characterised using spectral methods such as FT-IR, 1H NMR, and 13C NMR. Density functional theory (DFT) with the B3LYP/6-311G (d, p) level of theory was used to determine optimised bond parameters and single crystal XRD investigations confirmed the structure of DDIM. The results of single crystal XRD measurements aligned well with the optimised geometrical parameters from DFT calculations. Frontier molecular orbital computations provided insights into the molecule's stability, chemical reactivity and charge transfer. Atomic charges were determined using mulliken population analysis. The molecular electrostatic potential (MEP) mapped to electron density surfaces identified potential reactive sites. This molecule shows promise as a potential NLO material due to its high μβ0 value. Binding affinities were determined via molecular docking against the COVID-19 major protease (Mpro: 6WCF/6Y84/6LU7). A 100 ns molecular dynamics simulation under in silico physiological conditions confirmed the stability of the complex structure formed with the COVID-19 protein, revealing a stable conformation and binding pattern in an imidazole derivative environment. Additionally, in-silico analysis predicted favourable to moderate anti-viral activity and anticipated the compound's absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles.

The effect of strain effect on WS2 monolayer as a potential delivery carrier for anti-myocardial infarction drug: First-principles study.

Myocardial infarction is one of the major health challenges. It is of great significance to develop potential delivery carriers for new anti-myocardial infarction drugs. In this paper, based on first-principles calculations, monolayer WS2 with excellent photoelectric properties was verified as a carrier for the anti-myocardial infarction drug amiodarone (AMD). Studies have shown that the WS2-adsorbed AMD system (WS2@AMD) maintains structural stability and produces an adsorption energy of-2.12 eV. Mulliken charge analysis shows that electrons are transferred from WS2 atoms to AMD atoms. Among them, C, N and O obtained the maximum values of 0.51,0.37 and 0.56 e electrons, respectively, while H and I lost the maximum values of 0.32 and 0.24 e electrons, respectively. The optical response of WS2 adsorbed AMD system is similar to that of WS2. The light absorption coefficients of the two materials in the near ultraviolet region and the visible region can reach the order of 105 cm-1 and 104 cm-1, and the strain makes the light absorption peak red-shifted. The feasibility of temperature-controlled release mechanism of WS2 as AMD carrier was discussed. This theoretical work helps to improve the performance of two-dimensional nanomaterials and make them better as drug delivery carriers to improve the therapeutic effect of myocardial infarction. These results indicate that the WS2 monolayer has potential applications in the development of drug delivery carriers. In this study, based on first-principles calculations, the CASTEP simulation software package was used to study the structure and properties of materials. The interaction between electrons and ions is considered by using Ultrasoft pseudopotentials. In order to eliminate the spurious interaction between adjacent structures caused by periodic calculations, a vacuum space no less than 18 Å is placed in the vertical direction if necessary. Different functions may produce different density functional calculation results. Due to the low sensitivity of the crystal structure to the calculation details, the PBE functional under the generalized gradient approximation (GGA) was initially used for structural optimization, and the energy cutoff value was set to 500 eV. Grimme 's dispersion correction was used to make the results more accurate. The Brillouin zone (BZ) is sampled by a 7 × 7 × 1 K-point grid to ensure the reliability of the original lattice calculation. The lattice vector and atomic coordinates are relaxed, and the tolerance of each atom is less than 0.01 eV/Å. The energy tolerance at the atomic position is less than 10-7 eV/atom. When calculating the band gap, the HSE06 hybrid functional is used to modify the optimized structure of the PBE functional to obtain more accurate results. Spin-polarized DFT calculations were performed to calculate the electronic structure.

Investigating geometries and electronic states of boron and nitrogen Co-doping graphene nanoribbons from a DFTB algorithm

Self consistent charge-density functional tight binding simulations are used to investigate the effects of doping B and N atoms on structures and electronic states of armchair graphene nanoribbons passivated by H atoms at the ribbon edges. We considered ten different doping configurations of the doping ribbons, which are categorized into two groups based on whether B and N atoms are in the same carbon ring. The geometric configurations, energy, charge density differences, and Mulliken charges are characterized. The co-doping of B and N atoms in the ribbons significantly affects band structures for different doping arrangements. As covalent bonds form between B and C atoms, the Mulliken population on B atoms changes significantly when B and N atoms are located at different positions of the nanoribbons. The electrical information helps us understand how doping can adjust the electronic states of the graphene nanoribbons to meet the various requirements of electronic devices based on these nanoribbons.

Deciphering the molecular complexity: Employing density functional theory to probe 2-aminopyridinium 4-methyl benzene sulfonate elucidates synthesis methodologies, spectroscopic trends, reactivity patterns, molecular dynamics, and antibacterial properties

Harnessing computational modeling with density functional theory (DFT) and the B3LYP functional, delved into molecular geometry, harmonic spectra, and vibrational spectra for 2-aminopyridinium 4-methylbenzene sulfonate (2AP4MBS). Leveraging VEDA software to conduct a detailed investigation into oscillation spectra, particularly focusing on both quantitative and qualitative facets of infrared (IR) and Raman spectra. Our work also explored natural bonding orbitals, Fukui analysis, RDG analysis, and net Mulliken charge calculations, hinting at potential charge transfer within the molecule. Experimental validation of UV–Vis spectroscopic analyses was conducted. Electron density homology surface mapping via electrostatic potential interface (ESP) revealed insights into size, shape, charge density distribution, and reactivity sites. Topological features were elucidated through ELF and LOL maps.Docking simulations shed light on binding energy and interactions with peptide molecules, offering potential pharmaceutical applications following Lipinski criteria and ADMET framework assessments.

A molecular ground electronic state with an occupied 5g spinor-The superheavy (E125)F molecule.

Fully relativistic calculations, primarily at the 4-component coupled-cluster singles and doubles with perturbative triples [CCSD(T)] level of theory with the Dirac-Coulomb (DC) Hamiltonian, have been carried out for the superheavy (E125)F molecule using large Gaussian basis sets. The electronic ground state is determined to have an [Og]8s25g16f3 configuration on E125 with an Ω = 6 ground state and an 8p electron largely donated to F. A Mulliken population analysis indicates that the ground state is mainly ionic with a partial charge of +0.79 on E125 and a single sigma bond involving the F 2p and E125 8p spinors. The occupied g spinor is not involved in the bonding. With the largest basis set used in this work, the (0K) dissociation energy was calculated at the DC-CCSD(T) level of theory to be 7.02eV. Analogous calculations were also carried out for the E125 atom, both the neutral and its cation. The lowest energy electron configuration of E125+, [Og]8s1/225g7/216f5/23 with a J = 6 ground state, was found to be similar to that in (E125)F, while the neutral E125 atom has an [Og]8s1/225g7/216f5/227d3/218p1/21 ground state electron configuration with a J = 17/2 ground state. The ionization energy (IE) of E125 is reported for the first time and is calculated to be 4.70eV at the DC-CCSD(T) level of theory. Non-relativistic calculations were also carried out on the E125 atom and the (E125)F molecule. The non-relativistic ground state of the E125 atom was calculated to have a 5g5 ground state with an IE of just 3.4eV. The net effect of relativity on (E125)F is to stabilize its bonding.

Hex-star phosphorene nanosheets as sequencing material for DNA/RNA strands – A first-principles investigation

In this study, we utilised hex-star phosphorene as the main detecting material to identify the nucleobases. Nucleobases, being crucial carriers of hereditary information are identified through specific hydrogen bonding and steric interactions such as adenine pairing with thymine (or) uracil and guanine pairing with cytosine. The stable hex-star phosphorene possesses negative formation energy of −5.194 eV. The hex-star phosphorene exhibits a semiconductor nature with an energy band gap of 1.658 eV, which is deployed as the adsorbing substrate for nucleobases. Based on the Mulliken charge analysis, adsorption energy, relative band gap variation, and the detection efficiency of hex-star phosphorene towards nucleobases are examined. The outcome confirms the physisorption of nucleobases on hex-star phosphorene and strongly supports that hex-star phosphorene can be used as sequencing material for DNA and RNA.

Electrochemistry and DFT study of galvanic interaction on the surface of monoclinic pyrrhotite (0 0 1) and galena (1 0 0)

The electrochemical interaction between galena and monoclinic pyrrhotite was investigated to examine its impact on the physical and chemical properties of the mineral micro-surface. This investigation employed techniques such as electrochemistry, metal ion stripping, X-ray photoelectron spectroscopy, and quantum chemistry. The electrochemical test results demonstrate that the galena surface in the electro-couple system exhibits a lower electrostatic potential and higher electrochemical activity compared to the monoclinic pyrrhotite surface, rendering it more susceptible to oxidation dissolution. Monoclinic pyrrhotite significantly amplifies the corrosion rate of the galena surface. Mulliken charge population calculations indicate that electrons are consistently transferred from galena to monoclinic pyrrhotite, with the number of electron transfers on the mineral surface increasing as the interaction distance decreases. The analysis of state density revealed a shift in the surface state density of galena towards lower energy levels, resulting in decreased reactivity and increased difficulty for the reagent to adsorb onto the mineral surface. Conversely, monoclinic pyrrhotite exhibited an opposite trend. The XPS test results indicate that galvanic interaction leads to the formation of hydrophilic substances, PbSxOy and Pb(OH)2, on the surface of galena. Additionally, the surface of monoclinic pyrrhotite not only adsorbs Pb2+ but also undergoes S0 formation, thereby augmenting its hydrophobic nature.

Theoretical calculations of pyridine adsorption on the surfaces of Ti, Zr, N doped graphene

In this paper, the adsorption behavior of pyridine, a typical basic nitrogen compound in diesel oil, on Ti-doped, Zr-doped, N-doped and intrinsic graphene has been investigated by density functional methods. The corresponding adsorption energy, adsorption configurations, Mulliken charge transfer, differential charge density and density of states were discussed. The results show that doping graphene with metal atoms such as Ti or Zr can significantly obviously enhance the adsorption energy between pyridine and graphene surfaces, while non-metal N doping has a relatively minor effect. The magnitude of the adsorption energy of pyridine on the surfaces of graphene modified with different atoms follows the order: Ti-doped>Zr-doped>N-doped>intrinsic graphene. Pyridine interacts with Ti- or Zr-doped graphene through N−Ti, N−Zr and π−π interactions, while with N-doped and intrinsic graphene, it interacts via N−N, C−N and π−π interactions. There are significantelectron transfer and chemical bond formation between pyridine and metal-doped (Ti, Zr) graphene surfaces, indicating chemical adsorption. However, there is no chemical bond formation with non-metal N-doped graphene and intrinsic graphene, suggesting physical adsorption in these cases. Overall, pyridine exhibits more stable adsorption on the surfaces of Ti, Zr-doped graphene.

Doping strategies for β-Ga2O3 based on high-throughput first-principles calculations

β-Ga2O3 is a promising material for advanced optoelectronic semiconductors due to its wide bandgap and high breakdown voltage. However, achieving efficient p-type doping remains a challenge. This investigation employs high-throughput (HT) first-principles calculations to explore doping effects in β-Ga2O3 systematically. The results of HT first-principles calculations indicate that changes in the Fermi levels (EF) can reflect the type of dopant elements. We systematically evaluated nine candidate dopants using GGA+U calculations. Through analysis of the (0/−1) transition levels, the ability to form shallow acceptors gradually decreases in the order of Zn, Mg, Cu, Hg, and Ag. Interestingly, due to the GGA+U optimization process considering electron correlation and localization effects, Mg-doped β-Ga2O3 exhibits an impurity level near the conduction band minimum (CBM), contributed by Mg2p and O2p orbitals. Mulliken population analysis reveals that Cu exhibits the highest charge density after doping compared to Hg, Zn, and Mg. Additionally, Ag-doped β-Ga2O3 shows potential for UV device applications within the 200 nm to 280 nm spectrum. The insights from this study delineate effective p-type doping strategies for β-Ga2O3, contributing to the advancement of optoelectronic device development involving semiconductors.

Molecular Insights into Adhesion at Interface of Geopolymer Binder and Cement Mortar.

The degradation of concrete and reinforced concrete structures is a significant technical and economic challenge, requiring continuous repair and rehabilitation throughout their service life. Geopolymers (GPs), known for their high mechanical strength, low shrinkage, and durability, are being increasingly considered as alternatives to traditional repair materials. However, there is currently a lack of understanding regarding the interface bond properties between new geopolymer layers and old concrete substrates. In this paper, using advanced computational techniques, including quantum mechanical calculations and stochastic modeling, we explored the adsorption behavior and interaction mechanism of aluminosilicate oligomers with different Si/Al ratios forming the geopolymer gel structure and calcium silicate hydrate as the substrate at the interface bond region. We analyzed the electron density distributions of the highest occupied and lowest unoccupied molecular orbitals, examined the reactivity indices based on electron density functional theory, performed Mulliken charge population analysis, and evaluated global reactivity descriptors for the considered oligomers. The results elucidate the mechanisms of local and global reactivity of the oligomers, the equilibrium low-energy configurations of the oligomer structures adsorbed on the surface of C-(A)-S-H(I) (100), and their adsorption energies. These findings contribute to a better understanding of the adhesion properties of geopolymers and their potential as effective repair materials.

First-principles calculation on the interfacial stability, electronic structure and fracture mechanism of NbN/AlN interface

The interfacial stability of NbN(111)/AlN(0001) including interfacial energy, Wad(work of adhesion) and electronic structure were studied by first-principles calculation. The N1-Nb-cen interface(constructed with N1-terminated AlN(0001) and Nb-terminated NbN(111)) is determined to be the most stable interface which has the smallest interfacial distance(1.11 Å) and largest Wad(15.04 J/m2) among the 28 considered interface models. The electronic structure and ideal tensile stress of the N1-Nb-cen, N2-Nb-top, Al2-N-top and Al1-Nb-cen interfaces were also investigated. The AlN surface has stronger ionic bond than that in NbN surface according to the analysis of Mulliken charges. The bonding feature of N1-Nb-cen interface is ionic with strong covalent, while the other three interfaces have mainly ionic bond. The ideal tensile stress of the N2-Nb-top interface is the largest (22.88 GPa) at the strain of 17 %, which is larger than that of N1-Nb-cen interface. The fracture will occur at the interface for the Al2-N-top and Al1-Nb-cen interfaces, while it occurs at the AlN interior for the N1-Nb-cen and N2-Nb-top interfaces, due to the Wad of the N1-Nb-cen and N2-Nb-top interfaces are larger than the other two interfaces and atomic stacking of AlN surface.

Machine Learning-Aided Design of Highly Conductive Anion Exchange Membranes for Fuel Cells and Water Electrolyzers.

Alkaline anion exchange membrane (AEM)-based fuel cells (AEMFCs) and water electrolyzers (AEMWEs) are vital for enabling the efficient and large-scale utilization of hydrogen energy. However, the performance of such energy devices is impeded by the relatively low conductivity of AEMs. The conventional trial-and-error approach to designing membrane structures has proven to be both inefficient and costly. To address this challenge, a fully connected neural network (FCNN) model is developed based on acid-catalyzed AEMs to analyze the relationship between structure and conductivity among 180,000 AEM variations. Under machine learning guidance, anilinium cation-type membranes are designed and synthesized. Molecular dynamics simulations and Mulliken charge population analysis validated that the presence of a large anilinium cation domain is a result of the inductive effect of N+ and benzene rings. The interconnected anilinium cation domains facilitated the formation of a continuous ion transport channel within the AEMs. Additionally, the incorporation of the benzyl electron-withdrawing group heightened the inductive effect, leading to high conductivity AEM variant as screened by the machine learning model. Furthermore, based on the highly active and low-cost monomers given by machine learning, the large-scale synthesis of anilinium-based AEMs confirms the potential for commercial applications.