Characterization of Interatomic Potentials by a Calculation of Defect Energy

1997 ◽  
Vol 491 ◽  
Author(s):  
Y. Kogure ◽  
M. Doyama
Keyword(s):  
Molecular Dynamics ◽  
Noble Metals ◽  
Dynamics Simulation ◽  
Interatomic Potentials ◽  
Third Order ◽  
Jones Potential ◽  
Embedded Atom ◽  
Third Order Elastic Constants ◽  
Dynamics Simulations

ABSTRACTPotential functions used in molecular dynamics simulations for metals are characterized through a calculation of the third-order elastic constants, the Gruneisen parameters, and the molecular dynamics simulation of point defects. The Lennard-Jones potential and the embedded atom method potentials for noble metals (Cu, Ag, Au) are characterized by using a common program code.

Molecular Dynamics Simulation of Sputtering with Mmany-Body Interactions

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Low Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Many Body ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Small Single Crystal

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.

scholarly journals Molecular Dynamics Studies of the Melting of Copper with Vacancies amd Dislocations at High Pressures

MRS Advances ◽  
2017 ◽  
Vol 2 (48) ◽  
pp. 2597-2602 ◽  
Author(s):  
Clarence C Matthai ◽  
Jessica Rainbow
Keyword(s):  
Molecular Dynamics ◽  
Melting Temperature ◽  
Large Scale ◽  
High Pressures ◽  
Defect Density ◽  
Melting Process ◽  
Interatomic Potentials ◽  
Embedded Atom ◽  
Line Defects ◽  
Dynamics Simulations

ABSTRACTMolecular dynamics simulations of the melting process of bulk copper were performed using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) with the interatomic potentials being described by the embedded atom method. The aim of the study was to understand the effects of high pressures and defects on the melting temperature. The simulations were visualised using Visual Molecular Dynamics (VMD). The melting temperature of a perfect copper crystal, was found to be slightly higher than the experimentally observed value. The melting temperature as a function of pressure was determined and compared with experiment. Point and line defects, in the form of dislocations, were then introduced into crystal and the new melting temperature of the crystal determined. We find that the melting temperature decreases as the defect density is increased. Additionally, the slope of the melting temperature curve was found to decrease as the pressure was increased while the vacancy formation energy increases with pressure.

Characterization of Pt-Pd Bimetallic Nanoparticles by Cs-Corrected STEM

2013 ◽  
Vol 755 ◽  
pp. 69-74
Author(s):  
O. Téllez-Vázquez ◽  
R. Esparza ◽  
G. Rodríguez-Ortiz ◽  
Amado F. García-Ruiz ◽  
R. Pérez ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Metallic Nanoparticles ◽  
Bimetallic Nanoparticles ◽  
Good Control ◽  
Dynamics Simulation ◽  
Dynamical Analysis ◽  
Atomic Column ◽  
Dynamics Simulations ◽  
Average Size

Pt-Pd bimetallic nanoparticles were characterized using aberration (Cs) corrected scanning transmission electron microscopy (STEM) along with molecular dynamics simulations. The nanoparticles were synthesized through a microwave-assisted process. This technique has been applied to synthesize metallic nanoparticles at relatively short times, allowing a good control of size distribution. The structure of the bimetallic nanoparticles is fcc-like with an average size of 5 nm. To understand the properties of the bimetallic nanoparticles, it is necessary to know the positions of all the atoms in the nanostructure. We have used a recent quantitative method to analyze HAADF STEM images which allowed us to measure the total intensity of the scattered electrons for each atomic column. Beside with the characterization of the nanoparticles, we have performed classical molecular dynamics simulation for the structural and dynamical analysis of the cuboctahedral Pt-Pd bimetallic nanoparticles.

Choosing Appropriate Interatomic Potentials for Nanometric Molecular Dynamics (MD) Simulations

2016 ◽  
Vol 686 ◽  
pp. 194-199
Author(s):  
Akinjide O. Oluwajobi ◽  
Xun Chen
Keyword(s):  
Molecular Dynamics ◽  
Diamond Tool ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Interatomic Potentials ◽  
Embedded Atom ◽  
Pair Potentials ◽  
Empirical Potentials ◽  
Nanometric Machining ◽  
Cutting Processes

There is a need to choose appropriate interatomic empirical potentials for the molecular dynamics (MD) simulation of nanomachining, so as to represent chip formation and other cutting processes reliably. Popularly applied potentials namely; Lennard-Jones (LJ), Morse, Embedded Atom Method (EAM) and Tersoff were employed in the molecular dynamics simulation of nanometric machining of copper workpiece with diamond tool. The EAM potentials were used for the modelling of the copper-copper atom interactions. The pairs of EAM-Morse and EAM-LJ were used for the workpiece-tool (copper-diamond) atomic interface. The Tersoff potential was used for the carbon-carbon interactions in the diamond tool. Multi-pass simulations were carried out and it was observed that the EAM-LJ and the EAM-Morse pair potentials with the tool modelled as deformable with Tersoff potential were best suitable for the simulation. The former exhibit the lowest cutting forces and the latter has the lowest potential energy.

Molecular-Dynamics Study of the Amorphizatton of CuTi

1989 ◽  
Vol 157 ◽  
Author(s):  
Michael J. Sabochick ◽  
Nghi Q. Lam
Keyword(s):  
Molecular Dynamics ◽  
Pair Correlation ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Embedded Atom ◽  
Atomic Displacements ◽  
Chemical Disorder ◽  
Radiation Induced ◽  
System Energy ◽  
Dynamics Simulations

ABSTRACTRadiation-induced amorphization of the crystalline compound CuTi was investigated by molecular-dynamics simulations using new interatomic potentials derived from the embedded-atom method. Two different approaches to amorphization were tried: one in which Cu and Ti atoms were randomly exchanged, and another in which Frenkel pairs were introduced at random. The potential energy, volume expansion and pair-correlation function were calculated as functions of chemical disorder and atomic displacements. The results indicate that, although both chemical disordering and point-defect introduction increase the system energy and volume, the presence of Frenkel pairs is essential to trigger the crystalline-to-amorphous transition.

Some Thermodynamic Properties of NiAl Calculated by Molecular Dynamics Simulations

1988 ◽  
Vol 133 ◽  
Author(s):  
P. C. Clapp ◽  
M. J. Rubins ◽  
S. Charpenay ◽  
J. A. Rifkin ◽  
Z. Z. Yu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Boundary Energy ◽  
Alloy System ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Surface Energies ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Anti Phase Boundary

ABSTRACTCalculations of the surface free energy and anti-phase boundary energy as a function of low index orientations and temperature have been determined for equiatomic perfectly ordered bcc NiAl via molecular dynamics computer simulations. The simulations utilized an Embedded Atom Method calculation of the interatomic potentials and volume forces in the Ni-As alloy system. Values of about 0.95, 1.6, 1.9 and 2.0 J/m2 were found for surface energies of the {100}, {110}, {112} and {111} orientations:, respectively. APB energies of about 0.24 and 0.38 J/m2 were determined for {110} and {112} boundaries, respectively. In addition, we have examined the phase stability and relative energies of the ordered bcc, fcc and bct phases at low temperature, and find a bct phase with c/a = 1.32 slightly lower in energy than the bcc, presaging the martensitic transformation that occurs at finite temperatures in more nickel rich alloys.

Molecular Dynamics Study of (001) and (111) Thin Fcc Films

1990 ◽  
Vol 187 ◽  
Author(s):  
F.H. Streitz ◽  
K. Sieradzki ◽  
R. C. Cammarata
Keyword(s):  
Molecular Dynamics ◽  
Interatomic Potential ◽  
Analytic Form ◽  
Jones Potential ◽  
Lennard Jones ◽  
Embedded Atom ◽  
Atomic Interactions ◽  
Low Levels ◽  
Dynamics Simulations ◽  
Thermodynamic Instability

AbstractWe report on the results of molecular dynamics simulations of thin unsupported fcc films ranging in thickness from 20 layers to a monolayer. The films were oriented with either (001) or (111) free surface normals. The atomic interactions were modelled using a standard Lennard-Jones potential and a short range analytic form of the embedded atom potential. The elastic moduli of the films were determined by measuring their response to very low levels of applied stress.We find that the embedded atom and Lennard-Jones results are in relative agreement for (001) films and qualitative disagreement for (111) oriented films. We relate these differences to the nature of the interatomic potential and the thermodynamic instability of the (001) surface.

scholarly journals The effect of temperature and pressure on nitrogen adsorption in amorphous silica

2021 ◽  
Vol 2070 (1) ◽  
pp. 012045
Author(s):  
J. F. Fatriansyah ◽  
D. Dhaneswara ◽  
F. R. Kuskendrianto ◽  
M. H. Abdurrahman ◽  
M. B. Yusuf ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Amorphous Silica ◽  
Nitrogen Adsorption ◽  
Coulomb Force ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Jones Potential ◽  
Dynamics Simulations ◽  
Adsorption Phenomena

Abstract Nitrogen is an element that is widely found in nature can be used as a gas that is absorbed to help characterize materials, especially on the surface of the material. According to Brunauer – Emmet - Teller (BET) is a theory where nitrogen is used as a gas characterizing material because of its ability to high purity and can interact with solid elements and inert. BET can only produce quantitative data and does not show adsorption phenomena. Molecular dynamics simulation is conducted to observe the phenomena during nitrogen adsorption in amorphous silica, a porous material with a large surface area. In this study, the molecular dynamics simulations are arranged in a state of isotherm, where the temperature used is three variables: 77 K, 100 K, and 150 K in the variation of pressure used 1, 3, 5, 7, and 10 atm for each equilibrium. In molecular dynamics simulation to simulate the interaction between atoms based on Coulomb force is using Lennard-Jones Potential. Based on the simulation results obtain, it was found that at 77 K temperature had the optimal ability to adsorb nitrogen compared to 100 K and 150 K. The higher the pressure given in the system, it will increase the amount of nitrogen adsorbed.

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