Dissolution and Growth Kinetics of Small Crystals in Liquids

1991 ◽  
Vol 238 ◽  
Author(s):  
Michael J. Uttormark ◽  
Michael O. Thompson ◽  
Paulette Clancy
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Driving Force ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Equilibrium Melting Point ◽  
Small Crystals ◽  
Dynamics Simulations ◽  
Kinetics Of ◽  
Nucleation Phenomenon

ABSTRACTMolecular Dynamics simulations of the melting of small crystalline clusters (≃800 atoms) in the liquid have been performed at various temperatures above the equilibrium melting point. The melting rates as functions of size and temperature are derived and compared to that predicted by Classical Nucleation Theory. It is found that the driving force for the melting of clusters does not follow the form assumed in the theory, and that this difference is most apparent for clusters containing less than 300 atoms. The implications of these findings on nucleation phenomenon and possible sources for the discrepancies are discussed.

Molecular Dynamics Simulations on Melting of Aluminum

2013 ◽  
Vol 423-426 ◽  
pp. 935-938 ◽  
Author(s):  
Ji Feng Li ◽  
Xiao Ping Zhao ◽  
Jian Liu
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Molecular Dynamics Simulations ◽  
High Pressures ◽  
Ambient Pressure ◽  
Initial Porosity ◽  
Equilibrium Melting Point ◽  
Porosity Effect ◽  
Dynamics Simulations ◽  
Experimental Melting Point

Molecular dynamics simulations were performed to calculate the melting points of perfect crystalline aluminum to high pressures. Under ambientpressure, there exhibits about 20% superheating before melting compared to the experimental melting point. Under high pressures, thecalculated melting temperature increases with the pressure but at a decreasing rate, which agrees well with the Simon's melting equation. Porosity effect was also studied for aluminum crystals with various initial porosity at ambient pressure, which shows that the equilibrium melting point decreases with the initial porosity as experiments expect.

A study to investigate phase transitions and nucleation kinetics of nickel and copper

2016 ◽  
Vol 30 (11) ◽  
pp. 1650129 ◽  
Author(s):  
F. A. Celik ◽  
A. K. Yildiz
Keyword(s):  
Molecular Dynamics ◽  
Orientational Order ◽  
Nucleation Theory ◽  
Dynamics Simulation ◽  
Classical Nucleation Theory ◽  
Structural Development ◽  
Nucleation Kinetics ◽  
Embedded Atom ◽  
Bond Orientational Order ◽  
Kinetics Of

In this study, we investigate the homogeneous nucleation kinetics of copper and nickel system during cooling process using molecular dynamics simulation (MDS). The calculation is carried out for a different number of atoms consisting of 500, 2048, 8788 and 13,500 based on embedded atom method (EAM). It is observed that the melting points for the both model increases with increasing the size of systems (i.e. the number of atoms) as expected from Parrinello and Rahman MD method. The interfacial free energies and critical nucleus radius of nickel and copper are also determined by molecular dynamics, and the results are consistent with the classical nucleation theory. The structural development and phase transformation are also determined from the radial distribution function (RDF) and local bond orientational order parameters (LBOO).

Homogeneous nucleation of NaCl in supersaturated solutions

2021 ◽  
Author(s):  
Cintia Pulido Lamas ◽  
Jorge R. Espinosa ◽  
María Martín Conde ◽  
Jorge Ramirez ◽  
Pablo Montero de Hijes ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Homogeneous Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Approximate Approach ◽  
Seeding Method ◽  
Dynamics Simulations ◽  
Supersaturated Solutions

The Seeding method is an approximate approach to investigate nucleation that combines molecular dynamics simulations with classical nucleation theory. This technique has been successfully implemented in a broad range of...

scholarly journals Addressing the discrepancy of finding the equilibrium melting point of silicon using molecular dynamics simulations

2017 ◽  
Vol 473 (2202) ◽  
pp. 20170084 ◽  
Author(s):  
Saeed Zare Chavoshi ◽  
Shuozhi Xu ◽  
Saurav Goel
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Molecular Dynamics Simulations ◽  
Interatomic Potential ◽  
Melting Method ◽  
Molecular Systems ◽  
Equilibrium Melting Point ◽  
Wide Range ◽  
Dynamics Simulations ◽  
Solid Liquid

We performed molecular dynamics simulations to study the equilibrium melting point of silicon using (i) the solid–liquid coexistence method and (ii) the Gibbs free energy technique, and compared our novel results with the previously published results obtained from the Monte Carlo (MC) void-nucleated melting method based on the Tersoff-ARK interatomic potential (Agrawal et al. Phys. Rev. B 72 , 125206. ( doi:10.1103/PhysRevB.72.125206 )). Considerable discrepancy was observed (approx. 20%) between the former two methods and the MC void-nucleated melting result, leading us to question the applicability of the empirical MC void-nucleated melting method to study a wide range of atomic and molecular systems. A wider impact of the study is that it highlights the bottleneck of the Tersoff-ARK potential in correctly estimating the melting point of silicon.

scholarly journals Microscopic Evidence for Liquid-Liquid Separation in Supersaturated CaCO3 Solutions

Science ◽  
2013 ◽  
Vol 341 (6148) ◽  
pp. 885-889 ◽  
Author(s):  
Adam F. Wallace ◽  
Lester O. Hedges ◽  
Alejandro Fernandez-Martinez ◽  
Paolo Raiteri ◽  
Julian D. Gale ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Phase Separation ◽  
Liquid Phase ◽  
Lattice Gas ◽  
Solid Phase ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Liquid Separation ◽  
Dynamics Simulations ◽  
Dense Liquid

Recent experimental observations of the onset of calcium carbonate (CaCO3) mineralization suggest the emergence of a population of clusters that are stable rather than unstable as predicted by classical nucleation theory. This study uses molecular dynamics simulations to probe the structure, dynamics, and energetics of hydrated CaCO3 clusters and lattice gas simulations to explore the behavior of cluster populations before nucleation. Our results predict formation of a dense liquid phase through liquid-liquid separation within the concentration range in which clusters are observed. Coalescence and solidification of nanoscale droplets results in formation of a solid phase, the structure of which is consistent with amorphous CaCO3. The presence of a liquid-liquid binodal enables a diverse set of experimental observations to be reconciled within the context of established phase-separation mechanisms.

scholarly journals Nucleation Parameters of SPC/E And TIP4P/2005 Water Vapor Measured In NPT Molecular Dynamics Simulations

2022 ◽  
Author(s):  
Tomáš Němec
Keyword(s):  
Molecular Dynamics ◽  
Steady State ◽  
Water Vapor ◽  
Standard Deviation ◽  
Molecular Dynamics Simulations ◽  
Nucleation Rate ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Nucleation Process ◽  
Dynamics Simulations

Abstract Nucleation rates for droplet formation in water vapor are measured in molecular dynamics simulations of SPC/E and TIP4P/2005 water by monitoring individual nucleation events. The nucleation process is simulated in the NPT ensemble to evaluate the steady-state nucleation rate in accordance with the assumptions of classical nucleation theory (CNT). Nucleation rates measured between 300 K and 425 K for the SPC/E model, and between 325 K and 475 K for the TIP4P/2005 model, agree with the CNT predictions roughly within the standard deviation of the MD measurements of the nucleation rates.

scholarly journals Morphology, energetics and growth kinetics of diphenylalanine fibres

2021 ◽  
Author(s):  
Phillip Mark Rodger ◽  
Caroline Montgomery ◽  
Giovanni Costantini ◽  
Alison Rodger
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Growth Kinetics ◽  
Dynamics Simulations ◽  
Kinetics Of

The formation and stability of diphenylalanine fibres are studied by combining molecular dynamics simulations with microscopy and spectroscopy experiments, quantitatively detailing their morphology, energetics and growth kinetics.

Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Density Functional ◽  
Tight Binding ◽  
Combustion Process ◽  
Exponential Factor ◽  
Three Stages ◽  
Dynamics Simulations ◽  
Combustion Processes ◽  
Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

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