scholarly journals Размерная зависимость температуры плавления наночастиц кремния: молекулярно-динамическое и термодинамическое моделирование

2019 ◽  
Vol 53 (7) ◽  
pp. 964
Author(s):  
И.В. Талызин ◽  
М.В. Самсонов ◽  
В.М. Самсонов ◽  
М.Ю. Пушкарь ◽  
В.В. Дронников
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Melting Temperature ◽  
Atomistic Simulation ◽  
Thermodynamic Simulation ◽  
Simulation Based ◽  
Si Nanoparticles ◽  
Molecular Dynamics Results ◽  
Weber Potential ◽  
Limiting Value

Size dependence of the melting temperature of Si nanoparticles has been investigated combining molecular dynamics and thermodynamic simulation based on Thomson’s formula. The results of the atomistic simulation obtained by using the Stillinger-Weber potential agree with the results of other authors and with the thermodynamic simulation results predicting that the melting temperature T_m of Si nanoparticles diminishes under increasing their reciprocal radius R^(-1) following to the linear law. The available experimental data predict much lower values of T_m, including underestimated values of the limiting value T_m^((∞)) found by means of the linear extrapolation of experimental dots to R^(-1)→0 (i.e. to the particle radius R→∞), and the underestimation of T_m^((∞)) ranges from 200 to 300 K in comparison with the melting point 1688 K of the bulk crystalline Si. Taking into account the results obtained and their comparison with available results of other authors, a conclusion is made that molecular dynamics results, obtained by using the Stillinger-Weber potential, should be more adequate than the available experimental data on the melting temperature of Si nanoparticles.

Atomistic simulation of the uniaxial compression of black phosphorene nanotubes

2018 ◽  
Author(s):  
Van-Trang Nguyen ◽  
Minh-Quy Le
Keyword(s):  
Finite Element Method ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Uniaxial Compression ◽  
Critical Stress ◽  
Atomistic Simulation ◽  
Critical Strain ◽  
Bond Breaking ◽  
Black Phosphorene ◽  
Weber Potential

We study through molecular dynamics finite element method with Stillinger-Weber potential the uniaxial compression of (0, 24) armchair and (31, 0) zigzag black phosphorene nanotubes with approximately equal diameters. Young's modulus, critical stress and critical strain are estimated with various tube lengths. It is found that under uniaxial compression the (0, 24) armchair black phosphorene nanotube buckles, whereas the failure of the (31, 0) zigzag one is caused by local bond breaking near the boundary.

Charge transfer through a fragment of the respiratory complex I and its regulation: an atomistic simulation approach

2018 ◽  
Vol 20 (30) ◽  
pp. 20023-20032 ◽  
Author(s):  
Sehee Na ◽  
Sascha Jurkovic ◽  
Thorsten Friedrich ◽  
Thorsten Koslowski
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Complex I ◽  
Atomistic Simulation ◽  
Simulation Approach ◽  
Respiratory Complex ◽  
Initial Charge ◽  
Respiratory Complex I ◽  
Flow Through ◽  
Charge Flow

Using molecular dynamics and experimental data, we address the initial charge flow through the respiratory complex I and its regulation.

scholarly journals TO THE PROBLEM OF STABILITY OF NANOSCALE ISLAND FILMS AND EXTENDED FILMS WITH NANOSIZED THICKNESS

2020 ◽  
pp. 310-318
Author(s):  
Владимир Михайлович Самсонов ◽  
Игорь Владимирович Талызин
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Solid State ◽  
Melting Temperature ◽  
Island Films

Геометрическая нестабильность наноразмерных островковых пленок интерпретируется как проявление явления смачивания в твердом состоянии, а нестабильность сплошных пленок, наноразмерных по толщине, - как следствие десмачивания в твердом состоянии. С использованием молекулярно-динамического эксперимента исследованы закономерности и механизмы растекания твердых наночастиц Pb по различным граням Си при температуре, на 10 К ниже температуры плавления наночастиц выбранного размера (10 нм). Полученные в молекулярнодинамических экспериментах результаты сравниваются с экспериментальными данными, относящимися к микрочастицам Pb размером 5 -10 мкм. Установлено, что в одной и той же системе «островок-подложка» могут одновременно наблюдаться оба явления: смачивания в твердом состоянии и десмачивания в твердом состоянии. The geometric instability of nanoscale island films is interpreted as a manifestation of the solid state wetting phenomenon, and instability of continuous extended films with nanosized thickness as a consequence of the solid state dewetting. Using molecular dynamics experiment, regularities and mechanisms are investigated of spreading of Pb solid nanoparticles on different Cu faces at a temperature 10 K below the melting temperature of nanoparticles of the chosen size (10 nm). The results obtained in molecular dynamics experiments are compared with experimental data for Pb microparticles of 5 -10 pm in size. It has been also established that in the same «island -substrate» system both solid state wetting and solid state dewetting phenomena can simultaneously take place.

scholarly journals On the Conundrum of the Heat Capacityof Metallic Nanoclasters

2012 ◽  
Vol 14 (4) ◽  
pp. 305 ◽  
Author(s):  
V.M. Samsonov ◽  
Yu.Ya. Gafner ◽  
S.L. Gafner ◽  
I.S. Zamulin
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Heat Capacity ◽  
Bulk Phase ◽  
Surface Enthalpy ◽  
Metallic Nanoclusters ◽  
Small Clusters ◽  
Molecular Dynamics Results

<p>The heat capacity of nanoclusters was investigated using thermodynamics of surfaces, taking into account the surface enthalpy introduced by E. Guggenhein. It is shown that the cluster heat capacity <em>C<sub>p</sub></em> should be greater than the heat capacity of the corresponding bulk phase. However, the  ratio should not exceed 50% up to very small clusters containing 100 atoms. Theoretical estimations agree with molecular dynamics results. So, experimental data on metallic nanoclusters and nanostructures demonstrating that <em>C<sub>p</sub></em> exceeds  in 2-5 times should be incorrect.</p>

Improved Sampling Strategies for Protein Model Refinement based on Molecular Dynamics Simulation

2020 ◽  
Author(s):  
Lim Heo ◽  
Collin Arbour ◽  
Michael Feig
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Structure Prediction ◽  
Protein Structures ◽  
Conformational Space ◽  
Dynamics Simulation ◽  
Model Refinement ◽  
Protein Model ◽  
Lower Accuracy ◽  
Simulation Based

Protein structures provide valuable information for understanding biological processes. Protein structures can be determined by experimental methods such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, or cryogenic electron microscopy. As an alternative, in silico methods can be used to predict protein structures. Those methods utilize protein structure databases for structure prediction via template-based modeling or for training machine-learning models to generate predictions. Structure prediction for proteins distant from proteins with known structures often results in lower accuracy with respect to the true physiological structures. Physics-based protein model refinement methods can be applied to improve model accuracy in the predicted models. Refinement methods rely on conformational sampling around the predicted structures, and if structures closer to the native states are sampled, improvements in the model quality become possible. Molecular dynamics simulations have been especially successful for improving model qualities but although consistent refinement can be achieved, the improvements in model qualities are still moderate. To extend the refinement performance of a simulation-based protocol, we explored new schemes that focus on an optimized use of biasing functions and the application of increased simulation temperatures. In addition, we tested the use of alternative initial models so that the simulations can explore conformational space more broadly. Based on the insight of this analysis we are proposing a new refinement protocol that significantly outperformed previous state-of-the-art molecular dynamics simulation-based protocols in the benchmark tests described here. <br>

scholarly journals Defect Properties and Lithium Incorporation in Li2ZrO3

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3963
Author(s):  
Kobiny Antony Rex ◽  
Poobalasuntharam Iyngaran ◽  
Navaratnarajah Kuganathan ◽  
Alexander Chroneos
Keyword(s):  
Atomistic Simulation ◽  
Density Functional ◽  
Functional Theory ◽  
Lithium Zirconate ◽  
Simulation Based ◽  
Electrochemical Devices ◽  
Li Ion ◽  
Cluster Energy ◽  
Experimental Values ◽  
Lithium Incorporation

Lithium zirconate is a candidate material in the design of electrochemical devices and tritium breeding blankets. Here we employ an atomistic simulation based on the classical pair-wise potentials to examine the defect energetics, diffusion of Li-ions, and solution of dopants. The Li-Frenkel is the lowest defect energy process. The Li-Zr anti-site defect cluster energy is slightly higher than the Li-Frenkel. The Li-ion diffuses along the c axis with an activation energy of 0.55 eV agreeing with experimental values. The most favorable isovalent dopants on the Li and Zr sites were Na and Ti respectively. The formation of additional Li in this material can be processed by doping of Ga on the Zr site. Incorporation of Li was studied using density functional theory simulation. Li incorporation is exoergic with respect to isolated gas phase Li. Furthermore, the semiconducting nature of LZO turns metallic upon Li incorporation.

scholarly journals Local Structuring of Diketopyrrolopyrrole (DPP)-based Oligomers from Molecular Dynamics Simulations

2021 ◽  
Author(s):  
Maryam Reisjalali ◽  
J. Javier Burgos-Marmol ◽  
Rex Manurung ◽  
Alessandro Troisi
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
High Mobility ◽  
Semiconducting Polymers ◽  
Microscopic Structure ◽  
Dynamics Simulations

The microscopic structure of high mobility semiconducting polymers is known to be essential for their performance but it cannot be easily deduced from the available experimental data. A series of...

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