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The efficient capture of low‐pressure CO2 remains a significant challenge due to the lack of established multi‐complexation of CO2 to active sites in microporous materials. In this study, we introduce a novel concept of reversible multi‐complexation of CO2 to alkaline earth metal (AEM) ion pairs, utilizing a host site in ferrierite‐type zeolite (FER). This unique site constrains two AEM ions in proximity, thereby enhancing and isotopically spreading their electrostatic potentials within the zeolite cavity. This electrostatic potential‐engineered micropore can trap up to four CO2 molecules, forming M2+−(CO2)n−M2+ (n=0–4, M=Ca, Sr, Ba) complexes, where each CO2 molecule is stabilized by interactions between terminal oxygen (Ot) in CO2 and the AEM ions. Notably, the Ba2+ pair site exhibits higher thermodynamic stability for multiple adsorptions due to the optimal binding mode of Ba2+−Ot−Ba2+. Through high‐accuracy energy calculations, we have established the relationship among structure, CO2 uptake, and operating temperature/pressure, demonstrating that the Ba2+ pair site can capture four CO2 molecules even at concentrations as low as 400 ppm and at 298 K. Three of the four molecules of CO2 trapped were removable at room temperature and under vacuum. The findings in the present study provide a new direction for developing efficient CO2 adsorbents. [ABSTRACT FROM AUTHOR]

Emulsified asphalt finds extensive application in pavement repair, addressing issues like road ruts and cracks. While the adsorption behaviour of emulsifiers on oxide surfaces (CaCO3 and SiO2) of aggregates is influenced by the presence of phenyl functional groups, the precise mechanism of this influence remains insufficiently understood. This study employs molecular dynamics models and macroscopic experiments to investigate the mechanism involving emulsifiers, sodium ions, and water at aggregate interfaces, quantifying the role of phenyl functional groups from a molecular perspective. The results reveal the following: strong electrostatic attraction between alkaline aggregates and Na+, leading to substantial Na+ adsorption. The phenyl functional groups reduce diffusion coefficient, adsorption energy, and amounts in alkaline aggregates (−34.6%, −16%, −12.5%), while increasing them in acidic aggregates (+15.9%, + 14.7%, + 27.7%). The phenyl functional groups impact hydrogen bond acceptors, TPSA, and emulsifier complexity, altering adsorption. They enhance emulsifier electrostatic potential, affecting adsorption on different surfaces. In summary, this ongoing research framework aims to fine-tune emulsifiers through the use of phenyl functional groups, enhancing adsorption strength, adsorption amount, and diffusion between emulsifiers and aggregates. This work holds great significance for optimizing emulsifier molecular structures. HIGHLIGHTS: Strong electrostatic attraction between Na+ in the emulsifier and CO32- ions in the oxides (CaCO3 and SiO2) on the aggregate surface leads to a significant accumulation of Na+ on the surface of the alkaline aggregates. As the number of phenyl functional groups increases, the diffusion coefficient, adsorption energy, and adsorption capacity of emulsifiers in alkaline aggregate systems decrease significantly, and the opposite is true in acidic aggregate systems. The electrostatic potential distribution of emulsifier molecules in soap liquid is significantly affected by the hydrogen bond acceptor count, TPSA, and the complexity of the phenyl functional group. [ABSTRACT FROM AUTHOR]

To investigate the effects of ionic emulsifiers on the stabilization of emulsified asphalt, this paper used the Materials Studio software package to model a two-layer structure consisting of asphalt-emulsifier-water-emulsifier-asphalt. The principles of molecular dynamics were used to simulate the emulsified asphalt solution with various types of ionic emulsifier molecules. The effects of the anionic (SDS)/cationic (CTAB) emulsifiers on the stability of the emulsified asphalt were studied and compared. The following performance metrics were investigated: the interfacial monolayer morphology of the emulsifier molecules; the interaction energy between the emulsifier molecules and the water molecules; and the interaction energy between the emulsifier molecules and the asphalt phase/water phase. The results showed that, compared with CTAB emulsifier molecules, SDS emulsifier molecules had a higher extent of aggregation in the emulsified asphalt model system. The binding ability between the SDS emulsifier and the water molecules was stronger than that of the CTAB emulsifier molecules and negatively affects the stability of emulsified asphalt. Compared with the CTAB emulsified asphalt system, the SDS emulsified asphalt system has higher binding energy. In general, the stability of the CTAB-emulsified asphalt system is better than that of the SDS-emulsified asphalt system. [ABSTRACT FROM AUTHOR]

Nonlinear plasma solitons have been recently proposed as a possible, indirect way to detect dangerous small orbital debris in low Earth orbit. A kinetic simulation study of the interaction between small debris flowing through a plasma at hypersonic velocity is presented, with a particular focus on whether the debris-plasma interaction leads to the formation of ion-acoustic precursor solitons. By using an electrostatic kinetic model and in the absence of an external magnetic field, simulation results where the debris is treated as a Gaussian density source are compared with those where the debris-plasma interaction is modeled self-consistently, in both one and two dimensions. While ion-acoustic solitons are formed when the debris is treated as a Gaussian density source and the ions are cold, it is shown that self-consistent debris charging with similar parameters hinders the formation of precursor solitons. This indicates that self-consistent debris charging is key to quantitative predictions of soliton formation. Additionally, when the ion and electron temperatures are comparable, as typical of conditions in low Earth orbit, Landau damping physics also hinders the formation of ion-acoustic precursor solitons. These results suggest that it will be challenging to exploit ion-acoustic precursor solitons for orbital debris detection in low Earth orbit. [ABSTRACT FROM AUTHOR]

This study systematically investigated the influence of substituents (NH2, CH3, CF3, and Cl) on the keto-enol tautomerism of 1,2-cyclodiones, focusing on reactivity and thermodynamic stability. Calculations were performed using the M06-2X/6-311G++** level of theory, with a solvation model through CPCM/M06-2X/6-311G++**. Results indicate ring-size dependent tautomerism, with three-, five-, and six-membered rings favouring the keto-enol form, while four- and seven-membered rings favour the diketo form. The NH2 substituent uniquely stabilised the keto-enol form. Electron-donating groups generally stabilised the keto-enol form. Contrary to common expectations, a direct correlation between dipole moment and stability order was not universally observed within 1,2-cyclodione systems, with the NH2 group demonstrating nuanced effects. Similarly, dipole moment and electrostatic potential variance did not exhibit consistent correlation under the influence of different substituents. The diketo tautomer was generally found to be more reactive than the keto-enol form, especially in non-polar solvents. Surprisingly, substituent groups decreased the reactivity of the diketo form relative to the unsubstituted compound. [ABSTRACT FROM AUTHOR]

Context: Exploring potential energy surfaces (PES) is fundamental in computational chemistry, as it provides insights into the relationship between molecular energy, geometry, and chemical reactivity. We introduce Kick-MEP, a hybrid method for exploring the PES of atomic and molecular clusters, particularly those dominated by non-covalent interactions. Kick-MEP computes the Coulomb integral between the maximum and minimum electrostatic potential values on a 0.001 a.u. electron density isosurface for two interacting fragments. This approach efficiently estimates interaction energies and selects low-energy configurations at reduced computational cost. Kick-MEP was evaluated on silicon-lithium clusters, water clusters, and thymol encapsulated within Cucurbit[7]uril, consistently identifying the lowest energy structures, including global minima and relevant local minima. Methods: Kick-MEP generates an initial population of molecular structures using the stochastic Kick algorithm, which combines two molecular fragments (A and B). The molecular electrostatic potential (MEP) values on a 0.001 a.u. electron density isosurface for each fragment are used to compute the Coulomb integral between them. Structures with the lowest Coulomb integral are selected and refined through gradient-based optimization and DFT calculations at the PBE0-D3/Def2-TZVP level. Molecular docking simulations for the thymol-Cucurbit[7]uril complex using AutoDock Vina were performed for benchmarking. Kick-MEP was validated across different molecular systems, demonstrating its effectiveness in identifying the lowest energy structures, including global minima and relevant local minima, while maintaining a low computational cost. [ABSTRACT FROM AUTHOR]

Understanding and exploring the existence of a recognizable boundary between the noncovalent tetrel bond (TtB) and the coordination or weakened covalent bond are important for the bonding characterization. We have developed a simple methodology for analysing the type of bonds based on comparison of the electrostatic and total static potentials along the bond line. For the typical σ‐hole noncovalent bond formed by a Tt atom in a tetrahedral molecule, we have found that the space gap between positions of the maxima of the total static potential and the negative quantity of electrostatic potential is much wider than that for the coordination bonds in a trigonal bipyramid molecular system for the Cl−Tt/Cl⋅⋅⋅Tt and N−Tt/N⋅⋅⋅Tt (Tt=C, Si, Ge) bonds in molecules and molecular complexes. The distinction between the weakened covalent and strengthened noncovalent bonds is well reflected in behaviour of the Fermi hole along the bond line. Two‐factor empirical rule based on the superposition of the electrostatic and total static potentials is suggested. [ABSTRACT FROM AUTHOR]

Objective: to propose a new electrostatic theory for sap ascent in tall trees. Design/Methodology/Approach: we accomplished a detailed review of the different theories published regarding sap ascent by capillary in trees. The new theory proposed herein is based on some scientific studies of physiologists, biophysicists, and other branches of science, which expose the scientific bases of the water movement in the plant, but who have not proposed an integrated framework. Results: the proposed theory analyzed prior knowledge, then based on it, a new explanation is proposed for the ascent of sap in trees. Study Limitations/Implications: no field experiments were carried out to verify the increase in sap ascent in trees with heights greater than 40 m. Findings/Conclusions: this new theory helps to better explain water loss through transpiration and metabolic processes, since both are closely related to the water content in the mobile solution in conducting vessels. [ABSTRACT FROM AUTHOR]

Cholesterol, an essential lipid of cell membranes, regulates G protein-gated inwardly rectifying potassium (GIRK) channel activity. Previous studies have shown that cholesterol activates GIRK2 homotetrameric channels, which are expressed in dopaminergic neurons of the brain. Deletion of GIRK2 channels affects both GIRK2 homo- and heterotetrames and can lead to abnormal neuronal excitability, including conditions such as epilepsy and addiction. A 3.5 Á cryo-EM structure of GIRK2 in complex with CHS (cholesteryl hemisuccinate) and PIP2 (phosphatidylinositol 4,5-bisphosphate) has been solved. This structure provides the opportunity to study GIRK2 channel gating dynamics regulated by cholesterol using gating molecular dynamics (GMD) simulations. In the present study, we conducted microsecond-long GMD simulations on the GIRK2 channel in its APO, PIP2, and PIP2/CHS bound states, followed by systematic analysis to gain molecular insights into how CHS modulates GIRK2 channel gating. We found that CHS binding facilitates GIRK2 channel opening, with 43 K+ ion permeation events observed, compared to 0 and 2 K+ ion permeation events for GIRK2-APO and GIRK2/PIP2, respectively. Binding of CHS to the GIRK2 channel enhances PIP2 and channel interactions, which is consistent with previous experimental results. The negatively charged PIP2 alters the internal electrostatic potential field in the channel and lowers the negative free energy barrier for K+ ion permeation. [ABSTRACT FROM AUTHOR]

The ternary strategy has proven effective in enhancing the performance of organic solar cells (OSCs), yet identifying the optimal third component remains a challenge due to the lack of theoretical frameworks for predicting its impact based on molecular structure. This study addresses this challenge by proposing quantitative parameters derived from molecular surface electrostatic potential (ESP) as criteria for selecting ternary components. The asymmetric acceptor BTP‐OS, which exhibits a lower total average ESP and larger molecular polarization index relative to the host acceptor, is introduced into the PM6:L8‐BO system. This incorporation led to weakened ESP‐induced intermolecular interactions and reduce miscibility with donor polymer, resulting in an optimized multi‐scale morphology of the ternary blend. Consequently, the ternary device achieved an efficiency of 19.72%, one of the highest values for PM6:L8‐BO‐based ternary devices, with enhanced exciton dissociation and charge collection, lower energy disorder, and minimized non‐radiative energy losses. Comparable efficiency improvements are also verified in PM6:BTP‐eC9 and D18:N3 systems, demonstrating the broad applicability of the proposed approach. This study not only provides a practical and effective principle for selecting ternary components but also establishes a broader framework for optimizing ternary OSCs, potentially advancing the development of more efficient OSCs across diverse material systems. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have made remarkable progress due to developing novel materials and device architectures. Herein, we designed six new non-fullerene acceptors (QM1–QM6) having a quinoxalineimide (QI) as the central-building-block. We aimed to explore the potential of QI-containing structures for developing high-performance acceptors for OSCs. These designed molecules possess a fusion of the QI unit with a thienylthiophene backbone and are equipped with various efficient end-capping groups. Extensive theoretical calculations were carried out to evaluate the structural and charge distribution characteristics, including the optical, optoelectronics, density of states, transition density matrix, molecular electrostatic potential (ESP), reorganization energies, and photovoltaic properties. The results revealed that the designed series exhibited improved electron–hole pair coherences, efficient charge transportation, and favorable ESP patterns, suggesting their suitability for enhanced optical and electronic characteristics. Furthermore, the hole and electron overlap analyses demonstrated significant overlap in QM1–QM6, indicating efficient charge transfer and higher charge mobilities. Additionally, the analysis of reorganization energies showed low reorganization energy values, indicating favorable charge mobility rates and potential for high-efficiency solar cell devices. This research establishes a strong foundation for utilizing QI-containing fused units as central building blocks for designing high-performance acceptors, opening up new avenues for advancements in OSCs technology. We designed a series of new non-fullerene acceptors and explored their potential for organic photovoltaics. Various efficient theoretical calculations were carried out to evaluate the structural and charge distribution characteristics, including the optical, optoelectronics, density of states, and photovoltaic properties. This research establishes a strong foundation for designing high-performance acceptors, opening up new avenues for advancements in OSC technology. [ABSTRACT FROM AUTHOR]

This study examines the dynamical equation of the modified Korteweg–de Vries–Zakharov–Kuznetsov (mKdV-ZK), which is used to describe wave propagation in a dispersive and nonlinear medium. This equation is an extension of the well-known KdV-ZK equation, which has been extensively studied in the literature. In this study, we examine the solitary wave solutions of the (3+1)-dimensional mKdV-ZK equation using two analytical techniques: the generalized exp(−ϕ(ξ))-expansion approach and the two-variable (G′/G, 1/G)-expansion techniques. As a result, novel soliton solutions in a variety of forms, including Kink- and anti-Kink-type breather waves, dark and bright solitons, Kink soliton and multi-peak solitons, etc. are attained. The solitary wave solutions (which represent the electrostatic field potential), quantum statistical pressures, electric fields and magnetic fields are accomplished with the use of software. These solutions have numerous applications in various areas of physics and other sciences. These results also have applications in electromagnetic wave propagation, nonlinear optics, and plasma physics. Graphical representations of these results have also been presented. These results demonstrate the effectiveness of the two-variable expansion strategy, which will also be useful in solving many other nonlinear models that arise in mathematical physics and several other applied sciences fields. This work contributes to the advancement of novel wave manipulation and control methods, the construction of improved photonic devices for sensing and communications, and plasma confinement in fusion devices, among other uses. [ABSTRACT FROM AUTHOR]

The ability of an anion to serve as electron‐accepting Lewis acid in a noncovalent bond is assessed via DFT calculations. NH3 is taken as the common base, and is paired with a host of ACln− anions, with central atom A=Ca, Sr, Mg, Te, Sb, Hg, Zn, Ag, Ga, Ti, Sn, I, and B. Each anion reacts through its σ or π‐hole although the electrostatic potential of this hole is quite negative in most cases. Despite the contact between this negative hole and the negative region of the approaching nucleophile, the electrostatic component of the interaction energy of each bond is highly favorable, and accounts for more than half of the total attractive energy. The double negative charge of dianions precludes a stable complex with NH3. [ABSTRACT FROM AUTHOR]

Chalcogen bonds (ChB) are moderately strong, directional, and specific non‐covalent interactions that have garnered substantial interest over the last decades. Specifically, the presence of two σ‐holes offers great potential for crystal engineering, catalysis, biochemistry, and molecular sensing. However, ChB applications are currently hampered by a lack of methods to characterize and control chalcogen bonds. Here, we report on the influence of various substituents (halogens, cyano, and methyl groups) on the observed self‐complementary ChB networks of 2,1,3‐benzoselenadiazoles. From molecular electrostatic potential calculations, we show that the electrostatic surface potentials (ESP) of the σ‐holes on selenium are largely influenced by the electron‐withdrawing character of these substituents. Structural analyses via X‐ray diffraction reveal a variety of ChB geometries and binding modes that are rationalized via the computed ESP maps, although the structure of 5,6‐dimethyl‐2,1,3‐benzoselenadiazole also demonstrates the influence of steric interactions. 77Se solid‐state magic‐angle spinning NMR spectroscopy, in particular the analysis of the selenium chemical shift tensors, is found to be an effective probe able to characterize both structural and electrostatic features of these self‐complementary ChB systems. We find a positive correlation between the value of the ESP maxima at the σ‐holes and the experimentally measured 77Se isotropic chemical shift, while the skew of the chemical shift tensor is established as a metric which is reflective of the ChB binding motif. [ABSTRACT FROM AUTHOR]

Cirsilineol is a natural product that has pharmacological characteristics and is used to prevent the growth of cancer. This study aims to investigate the spectroscopic, electronic, and biological properties of drugs and predict their suitability for drug-like candidates to inhibit prostate cancer. The computational evaluation was performed with density functional theory (DFT) at B3LYP/6−311++G(d,p) level of theory and drug-like characteristics rendered from ADMET analysis. Spectral measurement for IR and Raman provided evidence of intra-molecular hydrogen bonding of the OH group in ring R1. The electronic transition properties of the title compound were determined using TD-DFT with a polarized continuum model in solvent ethanol, resulting in a blue shift in absorption wavelength. The electrostatic potential mapped with the van der Wall surface predicted effective electrophiles and nucleophiles, allowing for the layout of intra- and intermolecular hydrogen bonds. The pharmacological properties of cirsilineol determined by ADMED analysis confirmed that it is non-toxic. To assess the biological performance of cirsilineol, molecular docking was performed with protein codes 1E3G and 1GS4, which showed inhibition action with binding affinity −7.7 and −7.8 kcal/mol, respectively.

Viral variants of concern continue to arise for SARS-CoV-2, potentially impacting both methods for detection and mechanisms of action. Here, we investigate the effect of an evolving spike positive charge in SARS-CoV-2 variants and subsequent interactions with heparan sulfate and the angiotensin converting enzyme 2 (ACE2) in the glycocalyx. We show that the positively charged Omicron variant evolved enhanced binding rates to the negatively charged glycocalyx. Moreover, we discover that while the Omicron spike-ACE2 affinity is comparable to that of the Delta variant, the Omicron spike interactions with heparan sulfate are significantly enhanced, giving rise to a ternary complex of spike-heparan sulfate-ACE2 with a large proportion of double-bound and triple-bound ACE2. Our findings suggest that SARS-CoV-2 variants evolve to be more dependent on heparan sulfate in viral attachment and infection. This discovery enables us to engineer a second-generation lateral-flow test strip that harnesses both heparin and ACE2 to reliably detect all variants of concern, including Omicron.

β‐lactams are a chemically diverse group of molecules with a wide range of biological activities. Having recently observed curious trends in 2JHH coupling values in studies on this structural class, we sought to obtain a more comprehensive understanding of these diagnostic NMR parameters, specifically interrogating 1JCH, 2JCH, and 2JHH, to differentiate 3‐ and 4‐monosubstituted β‐lactams. Further investigation using computational chemistry methods was employed to explore the geometric and electronic origins for the observed and calculated differences between the two substitution patterns. [ABSTRACT FROM AUTHOR]

We present a novel solid form of monascin, an azaphilonoid derivative extracted from Monascus purpureus‐fermented rice. The crystal structure, C21H26O5, was characterized by single‐crystal X‐ray diffraction and belongs to the orthorhombic space group P212121. To gain insight into the electronic properties of the short contacts in the crystalline state of monascin, we utilized the Experimental Library of Multipolar Atom Model 2 (ELMAM2) database to transfer the electron density of monascin in its crystalline state. Hirshfeld surface analysis, fingerprint analysis, electronic properties and energetic characterization reveal that intermolecular C—H...O hydrogen bonds play a crucial role in the noncovalent bonding interactions by connecting molecules into two‐ and three‐dimensional networks. The molecular electrostatic potential (MEP) map of the monascin molecule demonstrates that negatively charged regions located at four O atoms are favoured binding sites for more positively charged amino acid residues during molecular recognition. In addition, powder X‐ray diffraction confirms that no transformation occurs during the crystallization of monascin. [ABSTRACT FROM AUTHOR]

Scorpion venoms have proven to be excellent sources of antimicrobial agents. However, although many of them have been functionally characterized, they remain underutilized as pharmacological agents, despite their evident therapeutic potential. In this review, we discuss the physicochemical properties of short scorpion venom antimicrobial peptides (ssAMPs). Being generally short (13–25 aa) and amidated, their proven antimicrobial activity is generally explained by parameters such as their net charge, the hydrophobic moment, or the degree of helicity. However, for a complete understanding of their biological activities, also considering the properties of the target membranes is of great relevance. Here, with an extensive analysis of the physicochemical, structural, and thermodynamic parameters associated with these biomolecules, we propose a theoretical framework for the rational design of new antimicrobial drugs. Through a comparison of these physicochemical properties with the bioactivity of ssAMPs in pathogenic bacteria such as Staphylococcus aureus or Acinetobacter baumannii, it is evident that in addition to the net charge, the hydrophobic moment, electrostatic energy, or intrinsic flexibility are determining parameters to understand their performance. Although the correlation between these parameters is very complex, the consensus of our analysis suggests that there is a delicate balance between them and that modifying one affects the rest. Understanding the contribution of lipid composition to their bioactivities is also underestimated, which suggests that for each peptide, there is a physiological context to consider for the rational design of new drugs. [ABSTRACT FROM AUTHOR]

A new green and highly sensitive method for the determination of rhodamine B (RhB) by deep eutectic solvent-based vortex-assisted liquid–liquid microextraction with fluorescence detection (DES-VALLME-FLD) was developed. The extraction efficiency of conventional solvents and different deep eutectic solvent (DES) systems composed of tetrabutylammonium bromide (TBAB) and an alcohol (hexanol, octanol, or decanol) in different ratios were compared. DFT calculations of intermolecular electrostatic and non-covalent interactions of the most stable RhB forms with DES and water explain the experimental DESs' extraction efficiency. Semiempirical PM7 computations were used to obtain Hansen solubility parameters, which supported the good solubility of the monocationic RhB form in selected DESs. The dependence of the linear calibration of microextraction into 100 µL DES was observed in the RhB calibration range from 0.2 to 10.0 µg L−1 with a correlation coefficient of R2 = 0.9991. The LOD value was calculated to be 0.023 µg L−1. The accuracy and precision of the proposed method were verified over two days with RSD values of 2.9 to 4.1% and recovery of 94.6 to 103.7%. The developed method was applied to the determination of RhB in real samples (tap water, energy drink, and lipstick). [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials have illustrated prominent interest with various usages in optoelectronics, nanoelectronics, and solar cells. Numerous physical behaviors of 2D materials have been explored for a category of monolayer transition metal dichalcogenides (TMDCs). These involve molybdenum disulfide (MoS2), molybdenum diselenite (MoSe2), and MoSSe Janus monolayers that have gained remarkable interest because of their distinguished optoelectronic features. Particularly, the band gap transitions of these TMDC materials undergo from indirect band gap transition to direct one by reducing the dimension from the bulk-counterpart to their MoS2, MoSe2, and MoSSe monolayers, respectively. To this end, we conducted a comparative investigation and analysis of the electronic structure behaviors as well as optical spectra of MoS2, MoSe2, and MoSSe monolayers. The optical absorption spectra of these 2D materials are ranging between the infrared (IR) and visible regimes for MoS2, MoSe2, and MoSSe sheets and the absorption of light emerges between 1.6 and 1.8 eV, corresponding to their semiconducting character. These 2D materials are potential candidates for solar cells and optoelectronic applications. [ABSTRACT FROM AUTHOR]

The utilization of long‐chain fluorocarbon surfactants is restricted due to environmental regulations, prompting a shift in the focus of research towards short‐chain fluorocarbon surfactants. The present study employs molecular dynamics techniques to model the behaviour of potassium perfluorobutylsulfonate (PFBS) at the n‐hexane/water interface, aiming to investigate the efficacy of short‐chain fluorocarbon surfactants in enhancing oil recovery. The findings suggest that ionized PFBS− has the ability to autonomously migrate to the oil/water interface, forming a layered thin film, with the sulfonic acid group being submerged in water, while the fluorocarbon chain is oriented towards the oil phase. This phenomenon aligns with the fundamental concept of surfactants in reducing interfacial tension between oil and water. The spontaneous dispersion process is supported by changes in the number of water molecules surrounding each PFBS− anion, as is well indicated by the number density distribution within the simulation box. Based on the analysis conducted by IGMH (Independent Gradient Model based on Hirshfeld partition), it was determined that sulfonic acid molecules are capable of forming hydrogen bonds with water molecules, whereas the interaction between fluorocarbon chains and the oil phase is predominantly characterized by weak van der Waals interactions. [ABSTRACT FROM AUTHOR]

Poisson's equation frequently emerges in many fields, yet its exact solution is rarely feasible, making the numerical approach notably valuable. This study aims to provide a tutorial-level guide to numerically solving Poisson's equation, focusing on estimating the electrostatic field and potential resulting from an axially symmetric Gaussian charge distribution. The Finite Difference Method is utilized to discretize the desired spatial domain into a grid of points and approximate the derivatives using finite difference approximations. The resulting system of linear equations is then tackled using the Successive Over-Relaxation technique. Our results suggest that the potential obtained from the direct integration of the distance-weighted charge density is a reasonable choice for Dirichlet boundary conditions. We examine a scenario involving a charge in free space; the numerical electrostatic potential is estimated to be within a tolerable error range compared to the exact solution. [ABSTRACT FROM AUTHOR]

Mineral oils and synthetic and natural esters are the predominant insulating liquids in electrical equipment. Structure–activity relationship models to predict the key properties of pure insulating liquids, including pulse breakdown strengths, AC breakdown voltages, dielectric constants, flash points, and kinematic viscosities, have been proposed for the first time. Dependence of the specific properties on the molecular structures has been illustrated quantitatively in terms of surface area, statistical total variance, and average deviation of positive and negative electrostatic potentials, as augmented by molecular weight, volume, and ovality. Moreover, the individual contribution of the functional groups to viscosity has been revealed by an additive approach. The predicted properties are in good agreement with the experimental data. The present theoretical work provides new insights on the development of novel dielectric fluids. [ABSTRACT FROM AUTHOR]

Heavy metals possess biological accumulation and toxicity, significantly endangering human health. Modified biochar adsorption is considered one of the most effective heavy metal removal techniques. In previous studies, explaining the microscopic mechanisms through macroscopic experiments was often difficult. This study employed multiple characterization methods to investigate the elemental composition, graphitization degree, and carbon chain structure of ZnCl2-modified biochar materials at a microscopic scale, analyzing the structural features of biochar and constructing a three-dimensional molecular structure monomer model of modified biochar. The quantum chemical density functional theory was introduced into the adsorption reaction between Pb2+ and biochar, calculating and analyzing the weak interactions during adsorption. The characterization results indicate that the molecular structure of ZnCl2-modified biochar is predominantly composed of polycyclic aromatic carbons with a molecular formula of C47H23NO12. Activated biochar forms abundant pore structures and contains abundant oxygen-containing functional groups on its pore surfaces. By calculation, it can be obtained that the adsorption reaction mainly occurs near oxygen-containing functional groups with high electron cloud density. Sites with negative charges and high charge numbers drive the adsorption of Pb2+ on the biochar surface, where weak ionic bonds, van der Waals forces, and cation -π interactions collectively promote Pb2+ adsorption on the biochar surface. Through analyzing simulated data, it was found that weak ionic bonding of aldehyde groups and van der Waals interactions of aromatic rings can synergistically enhance adsorption performance; the maximum adsorption energy under synergistic action is 119.25 kJ/mol. This study provides theoretical support for the practical application of modified biochar in removing heavy metal ions from soil. [ABSTRACT FROM AUTHOR]

Molecular dynamics method (MD) was used to study the distribution of potassium perfluoro (2-ethoxyethane) sulfonic acid (PESK) in water/gas systems. During the MD process, PES- spontaneously moves to the water surface, which is also the principle by which surfactants act. At equilibrium, most of the fluorocarbon chain faces the gas phase while the sulfonic acid radical faces the water, with a very small quantity of PES- and K+ is still in the bulk solution. The distribution of quantity density and charge density both confirm that PES- is mainly distributed at the water/gas interface. Weak intermolecular interactions were analyzed using the IGMH method, with the main interaction energy between PES- and water coming from h-bonds formed by the oxygen atom in the sulfonic acid group and hydrogen atom in water molecules. There is only van der Waals interaction between K+ and H2O molecules. The strength of the interaction between surfactants and water molecules was studied through energy decomposition. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole（SMX） is a broad-spectrum sulfonamide antibiotic. In this study, the B3LYP method of density functional theory（DFT） was used to optimize the initial configuration at the level of the B3LYP/6-311 + + G（d, p） basis set, and the most stable molecular structure was obtained. The bond length, bond angle and dihedral angle patameter values of SMX were given, and the molecule exhibited a non-planar structure. The frequency calculation was conducted at the same basis set level, and the infrared and Raman spectra of SMX were corrected and plotted using a frequency correction factor of 0.9630. The spectral bands were found to be mainly distributed in the frequency bands of 3600-2800 cm-1 and 1700-300 cm-1, and there are good agreement between the theoretically calculated and experimentally measured values, indicating that the DFT calculation method is desirable and credible. The GaussView 6.0 software package and the calculated potential energy distribution were used to assign each vibration mode within the frequency range. In addition, the electrostatic potential and frontline molecular orbitals of the SMX molecule were calculated and analyzed using the Multiwfn and VMD programs to predict the reactive sites of the molecule. These results provide basic data for detecting the vibration spectrum of SMX and are technical reference for its structural identification. [ABSTRACT FROM AUTHOR]

Properties of lithium- and hydrogen-bonded complexes formed by ammonia molecules, lithium halides (LiHal, A-complexes), and hydrogen halides (ННal, B-complexes) are aligned using quantum chemical MP2/aug-cc-pVTZ calculations. NBO analysis shows energy E(2) of inter-orbital interaction between the monomers grows upon the transition to heavier and less electronegative halogen, along with an increase in the contribution from the p-orbital to the hybrid orbital of lithium atom in A-complexes and the hybrid orbital of the halogen atom in B-complexes. The calculated value of E(2) correlates to the elongation of covalent Li−Hal and Н−Hal bonds as the complex forms. Analytical investigation of the topology of electron density predicts noteworthily higher values of the electron and potential energy densities at the critical point of intermolecular contact in B-complexes, relative to A-complexes, and a growing mutual penetration of atoms that form the intermolecular contact. The higher thermodynamic stability of lithium-bonded complexes could be due to the stronger positive electrostatic potential on the lithium atoms in molecules of lithium halides and the weaker exchange repulsion of the monomers that form an A-complex. [ABSTRACT FROM AUTHOR]

Empirical force field methods typically rely on point charges to describe the electrostatic interactions, which is problematic when anisotropy needs to be considered, as in the case of the electrostatic potential of covalently bound halogens that possess a positive site, termed σ -hole, surrounded by a large negative belt. To address this, an off-center point charge (extra point, EP) is usually placed at a given distance from the halogen to emulate the σ -hole and commonly used implementations are based on the restrained electrostatic potential (RESP) procedure to fit atomic charges, being one of the most used charge models. In this context, no specific Merz–Singh–Kollman (MK) radius for iodine is available in the literature, which is an essential parameter in the RESP fitting procedure. In this work, we explored the impact of the iodine MK radius on the obtained RESP charges for a set of 12 iodinated molecules. We verified that the relative root mean square (RRMS) values obtained with and without an EP kept decreasing with increasing radii for most compounds, thus impairing optimization using such a procedure. Nevertheless, the use of an iodine MK radius lower than 2 Å is not advisable since the RRMS kept decreasing considerably until this value was reached. Moreover, the performance of three iodine MK radii was studied with the estimation of the free energy of hydration (Δ G hyd) values using alchemical free energy calculations, which are particularly sensitive to the charges used. Despite the usage of different radii not leading to remarkable differences, our results indicate that using a value of 2.70 Å leads to lower mean absolute errors (MAE) and root mean squared error (RMSE) values when comparing the calculated with the experimental Δ G hyd values. Restrained Electrostatic Potential (RESP) charges are commonly used in force fields and Merz-Singh-Kollman (MK) radii are needed in the fitting. Since iodine radius is not available, in this work, we explored the impact of changing the iodine MK radius on the RESP charges of a set of 12 iodinated molecules and their hydration free energy predictions. Our results indicate that, although the changes are small, a value of 2.70 Angstrom leads to a better agreement with experimental values. [ABSTRACT FROM AUTHOR]

We studied intramolecular noncovalent bonds in organogermanium or organosilicon cyclic esters of tris(2-hydroxyalkyl)amines called silatranes and germatranes. We have shown that the N...Si and N...Ge interactions, well known as hypervalent or transannular bonds, can be rightfully categorized as the strong tetrel bonds (TtB). In the wide set of silatranes and germatranes, the TtB strength is under the influence of the Y substituent at Tt atom in the N...Tt–Y fragment and the features of crystalline environment. We have disclosed the quantitative trends in electronic features of N...Tt tetrel bonds and demonstrated the applicability of criteria based on the positions of extremes in electron density and electrostatic potential along the line between N and Tt atoms to compare the strength of the N...Si and N...Ge tetrel bonds. An important observation is that the dependence of gap width on bond lengths is not linear for silatranes. In order to solve this problem we have analyzed the features of total static potential. The gap between positions of extremes in electrostatic and total static potentials is wide for the weak tetrel bonds and narrow for the strong ones. [ABSTRACT FROM AUTHOR]

[Display omitted] The competitive interaction of oxyanions and humic nanoparticles (HNPs) with metal (hydr)oxide surfaces can be used to trace the ligand and charge distribution of adsorbed HNPs in relation to heterogeneity, fractionation, and conformational change. Batch adsorption experiments of HNPs on goethite were performed in the absence and presence of phosphate. The size of HNPs was measured with size exclusion chromatography. The Ligand and Charge Distribution (LCD) model framework was further developed to describe the simultaneous interaction of HNPs and phosphate with goethite. Preferential adsorption decreases the mean molar mass of adsorbed HNPs, independent of the phosphate presence, showing a linear dependency on the adsorbed HNPs fraction. Phosphate ion can be used as a probe to trace the distribution of functional groups and the variation in affinity of HNPs. The spatial distribution of adsorbed HNPs is driven by the potential gradients in the electrical double layer, which changes the conformation of the adsorbed HNPs. At the particle level, the adsorption of heterogeneous HNPs has an affinity distribution, which can be explained by the variation in molar mass (kDa) and density of the functional groups (mol kg−1) of the HNPs. The presented model can simultaneously describe the competitive adsorption of HNPs and phosphate in a consistent manner. [ABSTRACT FROM AUTHOR]

Context: Choline-based surfactants are interesting both from the practical point of view to obtaining environmental-friendly surfactants as well as from the theoretical side since the interactions between the choline and surfactants can help to understand self-assembly phenomena in deep eutectic solvents. Although no significant change was noticed in the micelle size and shape due to the exchange of the sodium counter-ion by choline in our simulations, the adsorption of the choline cation over the micelle surface is stronger than the adsorption of the sodium, which leads to a reduction of the exposed surface area of the micelle and remarkable effects over the electrostatic potential. The choline neutralizes the surface charge of the surfactant better than sodium; however, this is partially compensated by a stronger water orientation around the SDS micelle. The balance between the contributions from the surfactant, the counter-ion, and water to the electrostatic potential leads to a complex pattern with alternate regions of positive and negative potential at the micelle/water interface which can be important to the incorporation of other charged species at the micelle surface as well as for the interaction between micelles in solution. Methods: To evaluate the effects of the counter-ion substitution, micelles of sodium dodecyl sulfate (SDS) and choline dodecyl sulfate (ChDS) were studied and compared by means of molecular dynamics simulations in aqueous solution. In both cases, the simulations started from pre-assembled micelles with 60 dodecyl sulfate ions and 240-ns simulations were performed at NPT ensemble at T = 323.15 K and P = 1 bar using the Gromacs software with the OPLS-AA force field to describe dodecyl sulfate and choline, Åqvist parameters for sodium, and SPC model for water molecules. [ABSTRACT FROM AUTHOR]

The vanadate units have been theoretically investigated through density functional theory calculations. The global reactivity indices have been optimized. The obtained results revealed that the (Q0) [VO4]3-unit shows an electrondonor character, while the units Q1, Q2, and Q3 units are evidenced to exhibit an electron-acceptor feature. The transition from one unit to another is found to be accompanied by an increase in the number of bridging oxygen atoms, in accordance with the highlighted changes in Mulliken charges. Moreover, the analysis of the optimized electrostatic potential surfaces indicated a higher likelihood of nucleophilic attacks on the vanadium atoms. Predictions for infrared and Raman spectra were also conducted, revealing changes in symmetric and asymmetric vibrational bands as the number of bridging oxygen atoms varied. Additionally, Fukui indices were employed to identify the preferred sites for the electrophilic attack within the (Q0) [VO4]3-unit on the Q1, Q2, and Q3 vanadate units. [ABSTRACT FROM AUTHOR]

The modulation of electrostatic potential and optoelectronic characteristics of Janus MoSSe/MX2 (M = Mo, X = S, Se) van der Waals (vdW) heterostructures with strain engineering were studied by first principles. Based on the effection of uniaxial strain, the electronic properties of heterostructures not only are induced to form direct band gap and indirect band gap and even semiconductor-metal transformation, but also lead to strong interface-built electric field and excellent optical adsorption properties in the range of IR-visible. This work reveals the photophysical properties of MoSSe/MX2 vdW heterostructures as well as shows their strong potential for applications in novel optoelectronic devices and photocatalysis. [ABSTRACT FROM AUTHOR]

Defining life is an arduous task that has puzzled philosophers and scientists for centuries. Yet biology suffers from a lack of clear definition, putting biologists in a paradoxical situation where one can describe at the atomic level complex objects that remain globally poorly defined. One could assume that such descriptions make it possible to perfectly characterize living systems. However, many cases of misinterpretation put this assumption into perspective. In this article, we focus on critical parameters such as time, water, entropy, space, quantum properties, and electrostatic potential to redefine the nature of living matter, with special emphasis on biological coding. Where does the DNA double helix come from, why cannot the reproduction of living organisms occur without mutations, what are the limitations of the genetic code, and why do not all proteins have a stable three-dimensional structure? There are so many questions that cannot be resolved without considering the aforementioned parameters. Indeed, (i) time and space constrain many biological mechanisms and impose drastic solutions on living beings (enzymes, transporters); (ii) water controls the fidelity of DNA replication and the structure/disorder balance of proteins; (iii) entropy is the driving force of many enzymatic reactions and molecular interactions; (iv) quantum mechanisms explain why a molecule as simple as hydrocyanic acid (HCN) foreshadows the helical structure of DNA, how DNA is stabilized, why mutations occur, and how the Earth magnetic field can influence the migration of birds; (v) electrostatic potential controls epigenetic mechanisms, lipid raft functions, and virus infections. We consider that raising awareness of these basic parameters is critical for better understanding what life is, and how it handles order and chaos through a combination of genetic and epigenetic mechanisms. Thus, we propose to incorporate these parameters into the definition of life. [ABSTRACT FROM AUTHOR]

The family of Janus Kinases (JAKs) associated with the JAK–signal transducers and activators of transcription signaling pathway plays a vital role in the regulation of various cellular processes. The conformational change of JAKs is the fundamental steps for activation, affecting multiple intracellular signaling pathways. However, the transitional process from inactive to active kinase is still a mystery. This study is aimed at investigating the electrostatic properties and transitional states of JAK1 to a fully activation to a catalytically active enzyme. To achieve this goal, structures of the inhibited/activated full-length JAK1 were modelled and the energies of JAK1 with Tyrosine Kinase (TK) domain at different positions were calculated, and Dijkstra's method was applied to find the energetically smoothest path. Through a comparison of the energetically smoothest paths of kinase inactivating P733L and S703I mutations, an evaluation of the reasons why these mutations lead to negative or positive regulation of JAK1 are provided. Our energy analysis suggests that activation of JAK1 is thermodynamically spontaneous, with the inhibition resulting from an energy barrier at the initial steps of activation, specifically the release of the TK domain from the inhibited Four-point-one, Ezrin, Radixin, Moesin-PK cavity. Overall, this work provides insights into the potential pathway for TK translocation and the activation mechanism of JAK1. [ABSTRACT FROM AUTHOR]

This investigation introduces a new variational approach to refining Poisson's equation, enabling the inclusion of a broader spectrum of physical phenomena, particularly in the emerging fields of spintronics and the analysis of resonant structures. The innovative formulation extends the traditional capabilities of Poisson's equation, offering a nonlocal extension to classical theories of gravitation and opening new directions for energy conversion and enhanced communication technologies. By introducing a novel geometric structure,  ω ˜ , into the equation, a deeper understanding of electrostatic potentials is achieved, and the intricate dynamics of the gravitational potential in systems characterized by radial vorticity fluctuations are illuminated. Furthermore, the research elucidates the generation of longitudinal electromagnetic waves and resonant phenomena within dusty plasma media, thereby contributing to the methodological advances in the study of nonequilibrium systems. These theoretical advances have the potential to transform the understanding of complex physical systems and open up opportunities for significant technological achievements across a range of scientific sectors. [ABSTRACT FROM AUTHOR]

Theoretical studies for the bioactive nature of the molecule, 4-aminopyridine 4-aminopyridinium thiocyanate, performed by density function theory (DFT) studies and molecular docking, were simulated by a molecular electrostatic potential surface. Frontier molecular orbitals, molecular properties, and density of state of the spectrum were computed. On account of E HOMO and E LUMO showing their notable polarizability and number of reactivity parameters, they were calculated by DFT. The function of new scoring is to calculate the free energy change on binding in docking studies that exploit flexible ligands with macromolecular protein targets that have been evolved and tested. The protein β -catenin (1JPW) was docked and compared to the standard drug molecule doxorubicin in molecular docking studies. The obtained 4-aminopyridine 4-aminopyridinium crystals revealed the results that confirmed the studied compounds have significant anti-cancer properties. [ABSTRACT FROM AUTHOR]

During the coal mining process, gas explosions pose significant hazards, causing casualties and property losses. In order to develop new types of inhibitors for gas explosions, this paper explores the reaction mechanisms of urea pyrolysis products NH3 and HNCO inhibiting gas explosions based on density functional theory (DFT), transition state theory, and grand canonical ensemble Monte Carlo method (GCMC). It analyzes the reaction processes and kinetic characteristics of urea pyrolysis products with key radicals and gas molecules involved in explosions from a microscopic dynamic perspective. The results show that urea pyrolysis products exhibit good inhibition effects on active radicals involved in explosion reactions·NH3 and HNCO show stronger van der Waals forces in electrostatic attraction towards O2 and *H, respectively, and faster rate advantages in reaction rate constants. The lower Gibbs free energy barrier indicates higher reaction activity of pyrolysis products, thereby diluting the concentration of key radicals involved in explosion reactions and effectively inhibiting explosion key elementary reactions (R32, R38, R53, R57, R156, and R170). This study provides new insights into the microscopic inhibition mechanism of urea pyrolysis products on gas explosions, offering a new approach for designing more targeted modified inhibitors, which helps reduce the hazards of gas explosions during coal mining and provides scientific support and technical guidance for safe coal mining production.

We propose a novel structure of a charge trapping layer, that is doped between Word Line(WL) spaces in 3D NAND flash memory. To estimate the retention characteristics, the $\Delta \text{V}_{\mathrm {th}}$ of each structure by doping type is compared to a reference structure during retention operation. In this study, lateral charge spreading, rather than vertical loss, is mainly studied as an indicator to determine how long stored data can survive on the selected cell. When the SiN layer is doped with p-type, the electrostatic potential decreases and SRH recombination increases in the doping region. As a result, the p-type doping structure has better retention characteristics than others. In addition, for an optimized structure between retention characteristics and cell current, the doping region of the SiN layer is split and analyzed by the thickness of the doping region. Since the p-type doping region is thicker, lateral spreading is effectively blocked although the cell current decreased slightly.