scholarly journals Dislocation Mobility in Two-Dimensional Lennard-Jones Material

1999 ◽  
Vol 578 ◽  
Author(s):  
Nicholas P. Bailey ◽  
James P. Sethna ◽  
Christopher R. Myers
Keyword(s):  
Energy Barrier ◽  
Thermal Activation ◽  
Functional Form ◽  
Finite Energy ◽  
Atomistic Simulations ◽  
Two Dimensional ◽  
Jones Potential ◽  
Lennard Jones ◽  
Accurate Knowledge ◽  
Dimensional Crystal

AbstractIn seeking to understand at a microscopic level the response of dislocations to stress we have undertaken to study as completely as possible the simplest case: a single dislocation in a two dimensional crystal. The intention is that results from this study will be used as input parameters in larger length scale simulations involving many defects. We present atomistic simulations of defect motion in a two-dimensional material consisting of atoms interacting through a modified Lennard-Jones potential. We focus on the regime where the shear stress is smaller than its critical value, where there is a finite energy barrier for the dislocation to hop one lattice spacing. In this regime motion of the dislocation will occur as single hops through thermal activation over the barrier. Accurate knowledge of the barrier height is crucial for obtaining the rates of such processes. We have calculated the energy barrier as a function of two components of the stress tensor in a small system, and have obtained good fits to a functional form with only a few adjustable parameters.

Mechanical and Tribological Properties of Carbon Nanotubes Investigated with Atomistic Simulations

2000 ◽  
Vol 633 ◽  
Author(s):  
Boris Ni ◽  
Susan B. Sinnott
Keyword(s):  
Carbon Nanotubes ◽  
Atomistic Simulations ◽  
Many Body ◽  
Jones Potential ◽  
Diamond Surfaces ◽  
Empirical Potential ◽  
Mechanical And Tribological Properties ◽  
Lennard Jones ◽  
Walled Carbon Nanotubes ◽  
Nanotube Bundle

AbstractAtomistic simulations are used to better understand the behavior of bundles of single- walled carbon nanotubes that have been placed between two sliding diamond surfaces. A many-body reactive empirical potential for hydrocarbons that has been coupled to a Lennard-Jones potential is used to determine the energies and forces for all the atoms in the simulations. The results indicate that the degree of compression of the nanotube bundle between the nanotubes has a significant effect on the responses of the nanotubes to shear forces. However, no rolling of the nanotubes is predicted in contrast to previous studies of individual nanotubes moving on graphite.

STUDIES OF RATES OF CONVERSION AND POPULATIONS OF VARIOUS CONFORMATIONS OF SATURATED RING COMPOUNDS BY N.M.R.: I. CHLOROCYCLOHEXANE AND BROMOCYCLOHEXANE

1960 ◽  
Vol 38 (8) ◽  
pp. 1241-1248 ◽  
Author(s):  
L. W. Reeves ◽  
K. O. Strømme
Keyword(s):  
Energy Barrier ◽  
Room Temperature ◽  
Carbon Disulphide ◽  
Equilibrium Constants ◽  
Jones Potential ◽  
Lennard Jones ◽  
Ring Compounds ◽  
Saturated Ring ◽  
Van Der Waals Radii ◽  
Bromo Compound

The populations of equatorial and axial halogen forms of chloro- and bromo-cyclohexane have been studied by proton magnetic resonance between 25° and −104 °C in carbon disulphide solution. From the equilibrium constants obtained the free energy change between the two conformations is obtained. The bromo compound has 82% of the equatorial halogen form and the chloro compound 77%. Estimates of the populations are also available for room temperature from the chemical shift measurements. The energy barrier for conversion between the two forms is approximately 10,850 calories. A simple Lennard-Jones potential with the available estimates of van der Waals radii is used to calculate the differences in energy of the two forms.

scholarly journals Two-step melting of the Weeks-Chandler-Anderson system in two dimensions

Soft Matter ◽  
2021 ◽  
Author(s):  
Shubhendu Shekhar Khali ◽  
Dipanjan Chakraborty ◽  
Debasish Chaudhuri
Keyword(s):  
Numerical Simulation ◽  
Two Dimensions ◽  
Dimensional System ◽  
Lennard Jones Potential ◽  
Two Dimensional ◽  
Jones Potential ◽  
Lennard Jones ◽  
System Of Particles ◽  
Two Dimensional System ◽  
Repulsive Part

We present a detailed numerical simulation study of a two-dimensional system of particles interacting via the Weeks-Chandler-Anderson potential, the repulsive part of the Lennard-Jones potential. With the reduction of density,...

MASS DISTRIBUTION OF A TWO-DIMENSIONAL FRAGMENTATION PROCESS

2005 ◽  
Vol 16 (02) ◽  
pp. 253-258 ◽  
Author(s):  
L. E. ARARIPE ◽  
A. DIEHL ◽  
J. S. ANDRADE ◽  
R. N. COSTA FILHO
Keyword(s):  
Mass Distribution ◽  
Radial Component ◽  
Fragmentation Process ◽  
Lennard Jones Potential ◽  
Two Dimensional ◽  
Jones Potential ◽  
Lennard Jones ◽  
Mass Size ◽  
Dynamics Simulations ◽  
Number Of Particles

We perform extensive molecular dynamics simulations to study the mass size distribution of a two-dimensional fragmentation process. Our model consists of a large number of particles interacting through the Lennard–Jones potential. The fragmentation is induced by suddenly imposing a radial component on the particles' velocities, in order to mimic an explosion phenomenon. We then investigate the effect of the input energy on the resulting mass distribution of fragments.

Theoretical Analyses of Surface Interaction Stresses Considering Two-Dimensional Periodic Material Distributions

2017 ◽  
Author(s):  
Hiroshige Matsuoka ◽  
Ryoya Miyake ◽  
Satoru Maegawa ◽  
Shigehisa Fukui
Keyword(s):  
Half Space ◽  
Shear Stresses ◽  
Material Distribution ◽  
Two Dimensional ◽  
Jones Potential ◽  
Lennard Jones ◽  
Complex Fourier Series ◽  
Spatially Periodic ◽  
Basic Characteristics ◽  
Theoretical Analyses

The interaction stresses (pressure and shear stress) for (001) surface between a half-space consisting of a uniform material and a half-space with a spatially periodic material distribution have been derived based on the Lennard-Jones potential. The periodically distributed material property function is expanded as a complex Fourier series. The interaction pressures consist of non-fluctuation terms and fluctuation terms, while the shear stresses have only fluctuation terms. The interaction stresses for a distribution of two materials were then calculated as a typical example of a periodic material distribution. The basic characteristics of the interaction stresses are clarified.

scholarly journals Effect of Impurities on a Two-Dimensional Dodecagonal Quasicrystal

2021 ◽  
Author(s):  
Masahiro Fuwa ◽  
Masahide Sato
Keyword(s):  
Interaction Potential ◽  
Rotational Symmetry ◽  
Lennard Jones Potential ◽  
Two Dimensional ◽  
Jones Potential ◽  
Lennard Jones ◽  
Impurity Density ◽  
Effect Of Impurities ◽  
Potential Matrix ◽  
Dynamics Simulations

Abstract Langevin dynamics simulations are performed to examine how impurities affect two-dimensional dodecagonal quasicrystals. We assumed that the interaction potential between two particles is the Lennard-Jones-Gauss potential if at least one of these particles is a matrix particle and that the interaction potential between two impurities is the Lennard-Jones potential. Matrix particles and impurities impinge with constant rates on the substrate created by a part of a dodecagonal quasicrystal consisting of square and triangular tiles. The dependences of the twelve-fold rotational order and the number of shield-like tiles on the impurity density are examined after sufficient solid layers are grown. While the change in the twelve-fold rotational symmetry is small, the number of shield-like tiles in the solid increases greatly with increasing impurity density.

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