Molecular Dynamics Method Research Articles

Stacking interactions in stabilizing supramolecular assembly of M[9C]2M complexes: dynamic stability with remarkable nonlinear optical features.

Continual attempts have been made to discover excellent nonlinear optical (NLO) materials. Here, we investigate the role of stacking interactions and van der Waals forces in the designed parallel stacked complexes M[9C]2M (where M = Li, Na, K, Be, Mg, and Ca) using various quantum chemical and molecular dynamics methods. The thermodynamic stability of the present complexes is also revealed by the computed interaction energy, enthalpy of formation, and Gibbs free energy of formation (ΔGf). Molecular dynamics simulations were performed at room temperature to determine the stability of the dimer formation and their complexes. Alkali metals act as a more prominent source of excess electrons at long-range interaction distances. Charge decomposition analysis (CDA) and natural bonding orbital (NBO) analyses suggest excellent charge transfer in the alkalide complexes. In this series, Li[9C]2Li exhibits an excellent hyperpolarizability response up to 2.3 × 106 a.u., while Ca[9C]2Ca performs well in alkaline-earth metal complexes. The NLO response is mostly influenced by the alkalide and earthide characteristics. Dynamic NLO features were computed at externally applied frequencies. Scattering first hyperpolarizability (βHRS) and its associated components were also measured. The effect of solvents on hyperpolarizability is also considered. The quantum theory of atoms in molecules (QTAIM) and NCI are employed to investigate the bonding nature and vdW forces in addition to stacking interactions. TD-DFT and vibrational studies are also performed. We aim for this research to pave the way for the innovative strategies in designing supramolecular assemblies tailored for NLO applications.

Influence of energetic heavy ion sputtering on lifetime of alloy target

When energetic heavy ions are incident on negatively charged structure that collects and deposits ions, ion sputtering will occur. Metal wire is a structure commonly used for accelerating ions, the incidence of continuous high-throughput ions can cause surface loss of metal wire, affecting the service performance and lifespan of the metal wire. The SRIM software commonly used for calculating sputtering yield cannot consider the multi-body interaction problem contained in the alloy crystal structure. so, there is a significant error in calculating the sputtering yield of high-energy ions incident on alloy target. Based on the molecular dynamics method and Langevin temperature control model, the calculation model of ion sputtering parameters of energetic metal ions incident on alloy target is established in this work. The model is used to calculate the sputtering yield under the conditions of intact surface lattice of the target material and long-term incident surface lattice damage. The damages to the cathode metal wire under different incident ion fluences are further calculated, and the cross-sectional characterization of the metal wire is carried under typical working condition. The results show that the discrepancy between the experimental value and the theoretical value is less than 10%, which verifies the accuracy and applicability of the theoretical model. Based on this model, the search direction for sputtering resistant materials is proposed, meanwhile, a theoretical optimization is carried out to improve the service life of metal wire, and a method of using Ni-Ti alloy to improve the service life of metal wires is proposed, which is of great significance for predicting the service life of the metal wire under different conditions.

Stochastic dynamics mass spectrometric structural analysis of nucleotides

<span lang="EN-US">The paper deals with innovative equations tackling exactly stochastic dynamics mass spectrometric experimental variable intensity of peak per span of scan time. They overcome limitations of classical methods for semi-quantifying analytes developed, so far, and exactly grasp observable variables and their fluctuations; thus, succeeding in determining analytes reliably both quantitatively and 3D structurally via soft ionization mass spectrometry. </span><span lang="EN-US">Given the</span><span lang="EN-US"> paper’s goal of illustrating their crucial </span><span lang="EN-US">e</span><span lang="EN-US">ffect on mass spectrometric methodology as</span><span lang="EN-US"> an</span><span lang="EN-US"> irreplaceable approach to structurally analyse species, this study offers stochastic dynamics</span><span lang="EN-US">-</span><span lang="EN-US">based analysis of nucleotides. The major contribution </span><span lang="EN-US">is</span><span lang="EN-US"> providing empirical justification of aspects of structural mass spectrometry analysing uridines and pseudouridines. The virtual identity of fragmentation patterns causes significant analytical challenge</span><span lang="EN-US">s</span><span lang="EN-US">. The same is true for methyl-substituted guanosines which are often determined as mixtures. There </span><span lang="EN-US">are</span><span lang="EN-US"> used ultra-high resolution electrospray ionization mass spectrometry, high accuracy computational static and molecular dynamics methods, and chemometrics. The study discusses controversial aspects of classical techniques. It illustrates how the innovative equations resolve disputable problems of structural analysis of nucleotides. It supports advanced formulas for achieving superior performances. There are obtained coefficients of linear correlation </span><span lang="DE">|</span><em><span lang="EN-US">r</span></em><span lang="DE">|</span><span lang="EN-US"> = 0.9994–0.99923 determining N1-methyl-pseudouridine modified diphosphate compar</span><span lang="EN-US">ed</span><span lang="EN-US"> with 5-methyluridine diphosphate N-acetylglucosamine. There are determined N<sup>2</sup>,N<sup>2</sup>-dimethylguanosine, uridine, pseudouridine, 5-methyl-uridine, 1-methyl-pseudouridine, 5,6-dihydrothymidine, galactosyl-queuosine, mannosyl-queuosine, adenosine, 2’-O-methyl-5-hydroxymethyl</span><span lang="EN-US">cytidine, uridine triphosphate, thymidine diphosphate N-acetylglucosamine, 5-methyluridine diphosphate N-acetylglucosamine, and 7-methylguanosine-5’-phosphate modified derivative, respectively.</span>

Designing a Multi-Epitope Candidate Vaccine against Zika Virus NS5 Protein Through Immunoinformatics Approach for Producing in Plant Systems

Background: The Zika virus is an infectious virus that belongs to the Flaviviridae family. It is transmitted to humans through mosquito vectors and poses a serious threat to human health. Despite available resources, there is currently no effective and secure vaccine against the Zika virus to prevent such infections Objective: Observation of symptoms including fever, rash, joint pain, and conjunctivitis (red eyes) along with the possibility of severe complications during pregnancy, including birth defects such as microcephaly, is noted in infected individuals. So, it is the need of the hour to develop a potential vaccine that can immunize the human beings against this virus and protect them. For the purpose of vaccine development against the Zika virus, bioinformatics and immunoinformatics approaches are utilized. Materials and methods: Different epitopes from RdRp Protein of Zika virus were predicted including B-Cell and T- Cell epitopes. The selected epitopes were analyzed further in order to check their antigenicity, immunogenicity, solubility and toxicity in correspondence to their ability to initiate immune response in the individuals. The potential epitopes having the ability to trigger a good immune response and having non- toxic nature were utilized for vaccine development. By combining the different epitopes, a potential multi-epitope vaccine construct was developed. Combining of epitopes was done using EAAAK, AAY and GPGPG linkers. A 50S ribosomal protein was added at N terminal to improve the immunogenicity of the vaccine and 6-His tag protein also added at C terminal. Results: The constructed vaccine was found to have good population coverage all across the world. In molecular docking, strong interactions were found between the constructed vaccine and Toll-like receptor 3 (-346.16), suggesting their potential relevance in the immune response to the vaccine and dynamical stabilities were inspected through molecular dynamic (MD) simulation methods. The developed vaccine construct also exhibited good results of immune response in immune simulation and revealed that the constructed vaccine activates B and T lymphocytes which induce high levels of antibodies and cytokines to combat Zika infection. The constructed vaccine is an effective biomarker with non-toxicity, non-allergic properties, good immunogenicity, and antigenicity. However, experimental assays are required to verify the results of the present study. Conclusion: These findings suggest that design vaccine candidate effectively trigger immune response with no side effects against Zika virus. Keywords:- Zika virus vaccine, Epitope prediction, immunoinformatics, Multiepitope vaccine, Molecular docking.

Bimetallic CuNi Nanoparticle Formation: Solution Combustion Synthesis and Molecular Dynamic Approaches.

Nanomaterials are vital in catalysis, sensing, energy storage, and biomedicine and now incorporate multiprincipal element materials to meet evolving technological demands. However, achieving a uniform distribution of multiple elements in these nanomaterials poses significant challenges. In this study, various Cu-Ni compositions were used as a model system to investigate the formation of bimetallic nanoparticles by employing computer simulation molecular dynamics methods and comparing the results with observations from solution-combustion-synthesized materials of the same compositions. The findings reveal the successful synthesis of 12-18 nm bimetallic Cu-Ni nanoparticles with high phase homogeneity, alongside phase-segregated nanoparticles predicted by molecular dynamics simulations. Based on the comparison of the experimental and computational data, a possible scenario for phase segregation during the synthesis was proposed. It includes clustering of the atoms of the same type in an initial solution or the stage of gel formation and further developing segregation during the combustion/cooling stage. The research concludes that early synthesis stages, including particle preformation, significantly influence the phase homogeneity of multiprincipal element alloys. This study contributes to understanding nanomaterial formation, offering insights for improved alloy synthesis and enhanced functionalities in advanced applications.

Identification of novel inhibitors of cancer target telomerase using a dual structure-based pharmacophore approach to virtually screen libraries, molecular docking and validation by molecular dynamics simulations

In about 85% of cancer malignancies, replicative immortality caused by increased telomerase activity makes it an attractive target for developing anticancer therapeutics. However, the lack of approved small-molecule inhibitors rooted in the structural ambiguity of telomerase has impeded drug development for decades. In this study, we have exploited the FVYL pocket in the thumb domain, which plays a key role in the enzyme’s processivity. Due to the unavailability of a co-crystalized structure of BIBR1532 with the catalytic hTERT thumb domain, we utilized the molecular dynamics method to identify the precise binding site of the inhibitor. Two pharmacophore models were generated and validated for the putative (Site-I) and newly identified (Site-II) binding pockets which were screened virtually through the ChemDiv anticancer library, Otava drug-like green collection to identify novel lead compounds, and Binding database to screen out thumb domain-specific telomerase inhibitors. The top hits obtained were filtered using drug-likeliness parameters followed by redocking using a three-level screening strategy into their binding site. The structural investigation, molecular docking studies, and confirmatory molecular dynamics revealed that the exact binding site of BIBR1532 is away from the reported FVYL pocket with characteristic interactions conserved. Subsequently, the lead compounds with the highest docking scores and significant interactions in the newly discovered extended FVYL pocket were validated using 100 ns MD simulations. Additionally, cross-validated binding free energy calculations were performed using MM-PB(GB)SA methods followed by PCA and FEL characterization. The identified top lead compounds can be validated in vitro and taken forward for anticancer drug development.

Early Oxidation Kinetics of N-Dodecane under High-Temperature Conditions.

n-Dodecane(C12H26) is a typical surrogate fuel for aviation kerosene used in high-performance aero engines. The combustion kinetics of n-dodecane at temperatures above the critical point condition is the focus of attention in the aerospace field. In this paper, the first-principles molecular dynamics method is used to study the high-temperature oxidation of C12H26. Before C-C bond dissociation, C12H26 is oxidized to form oxidized C12 species containing multiple C═O, -OH, -O-, and -COOH groups, while releasing a large amount of energy. In addition, before the C-C bond dissociation of each C12H26, there are four main types of reactions: H-abstraction, H-addition, intramolecular H transfer, and O-addition. The H-abstraction and O-addition reactions have the highest frequencies. O2 molecules and H, OH, HO2, and O radicals also play important roles in promoting the oxidation of C12H26. The first investigation of the early oxidation reaction mechanism of C12H26 provides novel insights into the complex oxidation kinetics of long-chain alkanes.

Structural Features of Reverse AOT Micelles in Water/Cyclohexane: Molecular Dynamics Study

A study of the structural features of reverse micelles of Na AOT (sodium bis(2-ethylhexyl) sulfosuccinate) molecules in cyclohexane with an aqueous core was carried out using the molecular dynamics method. Reverse AOT micelles are formed in three-component systems containing a non-polar solvent, water, and AOT molecules at certain concentration ratios, expressed as w = [H2O]/[AOT]. A strong hydrogen bond between water molecules and AOT was found at the concentration w=6. For the first time, a sharp decrease in hydrogen bonding between water molecules and AOT at w=7 was shown, caused by a difference in the packing of AOT molecules and the collective dynamics of water molecules in the micelle core. The calculated results are in good agreement with experimental data from other authors. It is shown that, along with the methods of vibrational spectroscopy and dynamic light scattering, the molecular dynamics method is also informative for determining the structural characteristics of supramolecular structures and analyzing the collective dynamics of water molecules.

The high‐temperature creep behavior transition in stoichiometric nanocrystalline (Pux,U1−x)O2 mixed oxides

AbstractThe study of high‐temperature creep properties of (Pu,U)O2 mixed oxides (MOX) ceramics is an increasingly important and attractive issue in the field of nuclear fuels. Using the molecular dynamics method, we study the creep behavior and creep mechanism transition of nanocrystalline (NC) MOX affected by temperature, stress, grain size, and Pu contents. It is found that the creep of NC MOX is dominated by diffusional creep and larger stress can activate the grain boundary sliding. At the Bredig transition temperature of MOX, its anionic sublattice pre‐melts, which increases the creep rate due to intensified ions diffusion. Thus, the increase of temperature and stress leads to a transition in the creep mechanism from Coble creep with grain boundary sliding to Nabarro–Herring creep. Based on the method of analogy, we develop a theoretic model of the cationic vacancy concentration rate for high‐temperature diffusional creep of NC MOX. This model can well predict the cationic vacancy concentration in the secondary creep stage. The findings of this study could not only give us a deep understanding of the creep behaviors of MOX ceramics at higher temperatures, but provide valuable insights in the variations of cationic vacancy concentration during steady‐state creep stage of NC MOX.

Hydrated Calcium Silicate Erosion in Sulfate Environments a Molecular Dynamics Simulation Study.

To investigate the micro-mechanism of the erosion of hydrated calcium silicate (C-S-H gel) in a sulfate environment, a solid-liquid molecular dynamics model of C-S-H gel/sodium sulfate was developed. This model employs molecular dynamics methods to simulate the transport processes between C-S-H gel and corrosive ions at concentrations of 5%, 8%, and 10% sodium sulfate (Na2SO4), aiming to elucidate the interaction mechanism between sulfate and C-S-H gel. The micro-morphology of the eroded samples was also investigated using scanning electron microscopy (SEM). The findings indicate that the adsorption capacity of C-S-H for ions significantly increases with higher concentrations of Na2SO4 solution. Notably, the presence of sulfate ions facilitates the decalcification reaction of C-S-H, leading to the formation of swollen gypsum and AFt (ettringite). This process results not only in the hydrolysis of the C-S-H gel but also in an increase in the diffusion coefficients of Na+ and Ca2+, thereby exacerbating the erosion. Additionally, the pore surfaces of the C-S-H structure exhibited strong adsorption of Na+, and as the concentration of Na2SO4 solution increased, Na+ was more stably adsorbed onto the C-S-H pore surfaces via Na-Os bonds. The root-mean-square displacement curves of water molecules were significantly higher than those of SO42-, Na+ and Ca2+, which indicated that SO42- could co-penetrate and migrate with water molecules faster compared with other ions in the solution containing SO42-, resulting in stronger corrosion and hydrolysis effects on the C-S-H structure.

Molecular Dynamics Simulations in Nanoscale Heat Transfer: A Mini Review

Abstract As device miniaturization advances, managing heat at the nanoscale becomes increasingly critical. Nanoscale heat transfer presents unique challenges, including size effect, ballistic transport, and complex phonon interactions, which conventional macroscopic theories cannot fully address. Molecular dynamics (MD) simulations have been a powerful tool for directly modeling atomistic motion and interactions, offering valuable insights into thermal phenomena. This article provides an overview of MD methods and their contributions to understanding thermal transport in inorganic crystals, amorphous solids, polymers, and interfaces. Additionally, we offer our perspective on the emerging trends and future research directions in MD simulations, emphasizing their potential to unravel complex thermal phenomena and guide the design of next-generation thermal materials and devices.

Molecular dynamics study on the effect of ferrite structure on the mechanical characteristics of pearlite

Cold-drawn pearlitic steel wire has a wide range of applications in engineering due to its excellent mechanical properties. However, to date, there is limited understanding of how the internal ferrite phase structure of pearlitic steel wire affects its mechanical properties. The effect of the ferrite phase structure on the deformation mechanism and mechanical properties of pearlite was studied using molecular dynamics methods. The study considered three types of ferrite structures: (1) single-crystal structure, (2) nanocrystalline structure and (3) twinned crystal structure. The study showed that the ferrite structure could alter the deformation mechanism of pearlite during tensile loading by affecting the plastic deformation behaviour of ferrite. When the ferrite is a single-crystal structure, the pearlite undergoes elastic deformation followed by direct fracture failure; when the ferrite is a nanocrystalline structure, the pearlite experiences elastic deformation, elastic-plastic deformation, plastic deformation and then fracture failure in sequence; when the ferrite is a twin structure, the pearlite undergoes elastic deformation, plastic deformation and then fracture failure in sequence. Due to the influence of the deformation mechanism, the mechanical properties of pearlite with different ferrite structures showed a significant difference. Compared to single-crystal ferrite, when the ferrite structure is nanocrystalline, the strength of pearlite decreases significantly, but the ductility is significantly increased. Moreover, the ductility increases as the size of the nanocrystals decreases. Compared to single-crystal ferrite, when the ferrite has a twinned structure, the strength of the pearlite remains unchanged, but the ductility significantly increases. In addition, the ductility increases as the thickness of the twin layers decreases. The research results provide a new approach for further improving the mechanical properties of cold-drawn pearlitic steel wire.

Solvate Complex LiAlCl4·SO2: Synthesis and Physical-Chemical Properties.

This work describes the synthesis of the LiAlCl4·SO2 solvate complex and its properties. Its composition was determined using thermogravimetric analysis, Raman spectroscopy, and UV-vis spectroscopy. The specific ionic conductivity of LiAlCl4·SO2 is 4.7 × 10-2 S·cm-1. The dynamic viscosity is 19 cP at 25 °C, and the lithium transference number is 0.78. The melting point (+2.5 °C) and decomposition temperature (+60 °C) of LiAlCl4·SO2 were determined by simultaneous thermogravimetric analysis and differential scanning calorimetry. The structure of the solvate complex LiAlCl4·SO2 has been studied using a molecular dynamics method. A lithium cation is coordinated by one atom of Cl of the anion AlCl4- and one oxygen atom of SO2. The coordination number of lithium ions of LiAlCl4·SO2 is 4. The lithium cation is coordinated by three anions of AlCl4- and one molecule of SO2. Anion AlCl4- acts as a bridging ligand and binds different lithium cations.

Molecular Dynamics Simulation on Slippage Effect and Injection Capacity With Hydrophobic Nanoparticles Adsorption

ABSTRACTWith the continuous exploitation of global oil and gas resources, the focus of oilfield development has gradually shifted to low‐permeability and tight reservoirs. Nowadays the nanofluid has become one of the most important methods to enhance oil recovery in low‐permeability reservoir since the wettability and fluid flow characteristics can be changed as hydrophobic nanoparticles are adsorbed on the surface. In this study, we focus on the fluid slip characteristics feature of nanoparticles adsorbed with different adsorption degrees through molecular dynamics methods. Our results show that the adsorption of hydrophobic nanoparticles on the wall induces a velocity slip effect. The fluid flows in a Cassie state in the micro‐channel, with a significant increase in density, velocity, and slip length. In addition, the velocity in the mainstream area is significantly greater than that near the wall. The fluid flow rate within the pore channel is maximized and the most optimal adsorption degree is around 65.08%. Meanwhile, this study provides not only of great significance for the microscopic mechanism of pressure reduction and injection enhancement technology by nanoparticles adsorbed, but also an efficient method in enhance oil recovery in low‐permeability oil reservoirs.

Molecular Simulation of Adsorption of CO2 from a Combustion Exhaust Mixture of Zeolites with Different Topological Structures

In this work, a molecular simulation method was used to study the adsorption of seven combustion products (CO2, H2O, SO2, N2, O2, NO and NO2) on three zeolites with different topological structures (4A, MIF and MOR). Adsorption isotherms of pure components and mixtures at a wide range of temperatures (253–333 K) were calculated using the Monte Carlo method, obtaining equilibrium parameters including the adsorption capacity, adsorption heat and energy distribution. The calculation results indicated that 4A zeolite with more micropores has a stronger adsorption performance for CO2. The presence of water significantly reduced the CO2 capture efficiency of the three zeolites, and the CO2 adsorption amount decreased by more than 80%. Adsorption kinetics was studied using the molecular dynamic (MD) method, MFI and MOR, with channel-type pore structures exhibiting stronger gas diffusion performance, though their separation efficiency was not high. A 4A zeolite has the potential for kinetic separation of CO2.

Determining the solubility parameter and thermodynamic properties of beta-carotene in superheated water solvent by experimental and MD simulation methods

In this study, for the first time, the solubility of beta-carotene in green solvent was simulated using the molecular dynamics method. Superheated water was used as a solvent. The simulations were performed at different temperatures and a constant pressure of 2 MPa using Lammps software. The behavior of beta-carotene in solvent was investigated. The results showed that the dissolution process of beta-carotene in superheated water is endothermic and non-spontaneous, and increasing the temperature increases the dissolution of beta-carotene in superheated water. To ensure the results, the solubility of beta-carotene in superheated water was calculated using the static experimental method. The absolute average relative deviation between simulated and experimental beta-carotene solubility data in superheated water was 14.5 %. By increasing the temperature to 408.15 K, water under pressure became a solvent with the same behavior as organic solvents, and the solubility of beta-carotene, which was a lipophilic and insoluble compound in water, increased by about 80 times compared to ambient temperature. Accurately determining the solubility of this valuable medicinal plant in a green solvent can be used in the wide production of pharmaceutical, food, and cosmetic products.

Modeling the Transfer Properties of Helium and Hydrogen Isotopes by Thermodynamics and Molecular Dynamics Methods

Modeling the Transfer Properties of Helium and Hydrogen Isotopes by Thermodynamics and Molecular Dynamics Methods

Correlation and application of thermal expansion coefficient/elastic modulus for co-sintered composite cermet/ceramic materials

Deformation and stress concentration appearing during high-temperature sintering process significantly affect production quality of solid oxide cell (SOC), due to mismatched mechanical and thermophysical properties of the sintered electrode and electrolyte. In this study, a coarse-grained molecular dynamics (CG-MD) method is developed to evaluate and correlate coefficient of thermal expansion (CTE) and elastic modulus during the entire co-sintering process (including temperature-increasing, −insulation, and -decreasing stages). It is revealed that, in the sintered porous cermet electrode, CTE primarily exhibits an increasing trend until temperature-decreasing stage. Compared to the constant values commonly applied in the literature, the elastic modulus experiences a decay trend with a reduction of 32.14 % in the porous electrode and 9.68 % reduction in the dense electrolyte. The obtained CTE and elastic modulus are correlated with the sintering parameters and further applied to a macroscopical model for predicting overall sintering warpage and stress in a co-sintered SOC half-cell composed of a thick porous electrode and a thin dense layer. The varied CTE is identified as the main factor influencing warpage deformation, while the elastic modulus as a more significant impact on the von Mises stress during the co-sintering of the half-cell. Analysis is further conducted by orthogonal testing method for sintering temperature, sintering time, material content and diameter ratio of the porous cermet nanoparticles, aiming to optimize the varied CTE and elastic modulus, particularly during the temperature-insulation process. Subsequently, the optimized properties are implemented, and it is found that, after sintering insulation for 120 min, the maximum warpage displacement is about 7.34 mm, which represents a decrease of approximately 14.11 %; while the von Mises stress is observed to be 379.24 MPa, which indicates a reduction of around 37.33 % compared with the predictions by the constant properties.

Astrophysical study of dust collision using molecular dynamics method: an overview

Abstract Understanding dust collisions in astrophysical environments is essential for comprehending the formation and evolution of cosmic structures, such as planetary rings and interstellar clouds. This article reviews briefly studies on dust collision dynamics using the molecular dynamics (MD) method during the early stages of protoplanet formation. By simulating interactions at the atomic and molecular levels, researchers have actively explored the fundamental processes governing dust aggregation and fragmentation. This method incorporates essential aspects such as surface energy and viscoelastic behavior through interaction potentials between atomic particles. MD simulations cover a wide range of physical conditions, including varying impact velocities, particle sizes, and material compositions, to provide a thorough understanding of collision outcomes. The results identify critical thresholds for sticking, bouncing, and fragmentation, enhancing broader astrophysical models of dust evolution. This work underscores the significance of cohesive forces and material properties in determining collision behavior. The presented model involves the collision of two dust aggregates, each consisting of a few million atomic particles, at impact velocities around the threshold value, known as the bouncing velocity (Vb ), evaluated using the macroscopic Johnson-Kendall-Roberts (JKR) model. The model material mainly consists of silica, as the main material of rocky planets and water, which is widely distributed across the solar system. The findings demonstrate the range of validity of the JKR theory at the atomic scale, influenced by the complexity of the internal structure of the colliding agents. These insights contribute to our understanding of dust growth mechanisms in protoplanetary disks, advancing knowledge of cosmic dust dynamics and its implications for planet formation and the interstellar medium. The simulation data can also refine larger-scale modeling methods, such as granular mechanics.

Structure patterns of one-step synthesis of CuNi nanopowders in air environment: Experiment and atomistic simulations

A possibility for one-step synthesis of bimetallic CuNi nanopowders in a different ratio of Ni to Cu by solution combustion synthesis technique under normal air atmosphere without any post reduction is reported. The effect of different types of fuels like citric acid and glycine on the combustion process and characteristics of resultant solid products were investigated. XRD results showed the existing of CuNi as a main phase and small amounts of CuO and (Ni,Cu)4N. Determined CuNi particle sizes were in the range of up to 50 nm. Computer simulation was performed using the molecular dynamics method for similar concentration compositions, but in size range of 4.5–5.5 nm, as a result of cooling the system from 1700 K to 300 K. In addition, two types of melting scenario of binary CuNi NPs were studied: 1) heterogeneous melting of monocrystalline Cu and Ni NPs; 2) melting of the crystallization products of binary NPs. Melting temperatures weakly depend on the choice of the above-mentioned melting scenario. However, the nature of subsequent crystallization can be influenced by the initial energy of the system, which is higher for case 1. The characteristic temperatures of phase transitions of melting and crystallization are determined based on the analysis of hysteresis loops of the specific potential part of the internal energy of NPs. The patterns of atomic and structural segregation in binary CuNi NPs were studied.