Computer-simulated amorphous structures (I). Quenching of a Lennard-Jones model system

Kristensen, W. Damgaard

doi:10.1016/0022-3093(76)90023-5

Cited by 82 publications

(10 citation statements)

References 15 publications

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“…The grains are amorphous with a radius of and have been constructed by rapidly quenching from the melt 29 , 30 with a rate exceeding 0.007 in Lennard–Jones units 31 . We verified that the pair correlation function agrees with that published in the literature 32 , 33 . The grains are relaxed in an NVE ensemble with velocity-proportional damping for a LJ time of 460 in order to obtain relaxed surfaces.…”

Section: Methodssupporting

confidence: 88%

Molecular dynamics of rolling and twisting motion of amorphous nanoparticles

Umstätter

Urbassek

2021

Sci Rep

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Granular mechanics codes use macroscopic laws to describe the damping of rolling and twisting motion in granular ensembles. We employ molecular dynamics simulation of amorphous Lennard–Jones grains to explore the applicability of these laws for nm-sized particles. We find the adhesive force to be linear in the intergrain attraction, as in the macroscopic theory. However, the damping torque of rolling motion is strongly superlinear in the intergrain attraction. This is caused by the strong increase of the ‘lever arm’ responsible for the damping torque—characterizing the asymmetry of the adhesive neck during rolling motion—with the surface energy of the grains. Also the damping torque of twisting motion follows the macroscopic theory based on sliding friction, which predicts the torque to increase whit the cube of the contact radius; here the dynamic increase of the contact radius with angular velocity is taken into account.

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Section: Methodssupporting

confidence: 88%

Molecular dynamics of rolling and twisting motion of amorphous nanoparticles

Umstätter

Urbassek

2021

Sci Rep

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“…6 Figure 1 shows our data in reduced units 7 ; note that the diffusion coefficient at T =0.25 is smaller by about two orders of magnitude than its value at T m = 0.62. Equation (1) correctly predicts the temperature dependence of the crystallization rate of Ge0 2 , for example, over a 400-degree temperature range, in which the viscosity changes by five orders of magnitude.…”

mentioning

confidence: 92%

Crystallization Rates of a Lennard-Jones Liquid

Broughton¹,

Gilmer²,

Jackson³

1982

Phys. Rev. Lett.

342

215

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“…The {100} crystal facets are chosen for studying facet contacts and some sharp crystal edges are randomly chosen for studying the edge contact problem. The amorphous structure is obtained by quenching a molten argon block from temperature T = 70 K to 0.02 K at a rate of 8 × 10 10 K s −1 [21,22], followed by equilibrations at T eq = 0.02 K. A nearly spherical nanoparticle is then created by cutting the block in equilibrium. Radial distribution functions computed from our equilibrated nanoparticles confirm the amorphous structure [23].…”

Section: Numerical Simulations (A) Modelsmentioning

confidence: 99%

Small nanoparticles, surface geometry and contact forces

2018

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In this molecular dynamics study, we examine the local surface geometric effects of the normal impact force between two approximately spherical nanoparticles that collide in a vacuum. Three types of surface geometries-(i) crystal facets, (ii) sharp edges, and (iii) amorphous surfaces of small nanoparticles with radii <10 nm-are considered. The impact forces are compared with their macroscopic counterparts described by nonlinear contact forces based on Hertz contact mechanics. In our simulations, edge and amorphous surface contacts with weak surface energy reveal that the average impact forces are in excellent agreement with the Hertz contact force. On the other hand, facet collisions show a linearly increasing force with increasing compression. Our results suggest that the nearly spherical nanoparticles are likely to enable some nonlinear dynamic phenomena, such as breathers and solitary waves observed in granular materials, both originating from the nonlinear contact force.

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Computer-simulated amorphous structures (I). Quenching of a Lennard-Jones model system

Cited by 82 publications

References 15 publications

Molecular dynamics of rolling and twisting motion of amorphous nanoparticles

Molecular dynamics of rolling and twisting motion of amorphous nanoparticles

Crystallization Rates of a Lennard-Jones Liquid

Small nanoparticles, surface geometry and contact forces

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