Molecular Dynamics Simulations of Supercooled Liquid Metals and Glasses

2000 ◽  
Vol 644 ◽  
Author(s):  
Hyon-Jee Lee ◽  
Yue Qi ◽  
Alejandro Strachan ◽  
Tahir Cagin ◽  
William A. Goddard ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Liquid State ◽  
Liquid Metals ◽  
Alloy System ◽  
Supercooled Liquid ◽  
Packing Fraction ◽  
Solute Concentration ◽  
Dynamics Simulation ◽  
Dynamics Simulations

AbstractThe thermodynamic, transport and structural properties of a binary metallic glass former in solid, liquid, and glass phases were studied using molecular dynamics simulation. We used a model binary alloy system with a sufficient atomic size mismatch and observed a glass transition in a quenching process. The diffusivity and viscosity were calculated in the liquid state and the super-cooled liquid state. The smaller atom showed higher diffusivity and more configurational randomness compared to the larger atom. The viscosity increased abruptly around the glass transition temperature. The solvent/solute concentration effect on the glass transition was examined in terms of a packing fraction. We find that the glass forming ability increases with the packing fraction in the liquid state because the densely-packed material requires more time to rearrange and crystallize.

Molecular Dynamics Simulation of the Glass Transition of Ortho-Terphenyl in Bulk and Thin Films

2006 ◽  
Vol 924 ◽  
Author(s):  
Jayeeta Ghosh ◽  
Roland Faller
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
A Priori ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Technological Advancement ◽  
Atomistic Model ◽  
Reorientation Dynamics ◽  
Bulk Model ◽  
Dynamics Simulations

ABSTRACTThe glass transition temperature in thin film depends strongly on film thickness and interaction with the substrate and it is normally a priori not clear which way it deviates from the bulk value. This causes new challenge in the technological advancement of smaller and smaller electronic devices. In this study molecular dynamics simulations of a low-molecular weight organic glass former, ortho-terphenyl, are carried out in bulk and freestanding films. The main motivation is to provide insight into the confinement effect without interface interactions. Based on earlier models of ortho-terphenyl we developed an atomistic model for bulk simulations. The model reproduces the literature data from simulations as well as experiments. After characterizing the bulk model we form a freestanding film. This film gives us the opportunity to study the dynamical heterogeneity near the glass transition by in-plane mobility and reorientation dynamics. We also develop a structurally coarse-grained model for this glass former based on our atomistic model to study bigger system for a longer period of time.

Atomic Motion in Amorphous Ni81B19 Studied by Reverse Monte Carlo and Molecular Dynamics Simulation

1993 ◽  
Vol 321 ◽  
Author(s):  
Barend J. Thijsse ◽  
Leon Van Ee ◽  
Jilt Sietsma
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Glass Transition ◽  
Molecular Dynamics Simulation ◽  
Monte Carlo Method ◽  
Dynamics Simulation ◽  
Atomic Motion ◽  
Reverse Monte Carlo ◽  
Dynamics Simulations ◽  
Reverse Monte Carlo Method

ABSTRACTMolecular dynamics simulations of glassy Ni81B19, starting with a configuration obtained by the Reverse Monte Carlo Method, indicate a calorimetrie glass transition at 960 K and point to a significant change in the atomic dynamics between 960 and 1200 K. Above this range, normal liquid-like behavior is found; at lower temperatures, we find a residual diffusivity and cooperative atomic Motion. Atomic jumps are processes smeared out in time and space over continuous rather than discrete scales.

A new cubic Ia3̅d crystal structure observed in a model single component system by molecular dynamics simulation

2018 ◽  
Vol 233 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Konstantin A. Lokshin ◽  
Valentin A. Levashov ◽  
Maxim V. Lobanov
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Soft Matter ◽  
Pair Potential ◽  
Md Simulations ◽  
Packing Fraction ◽  
Single Component ◽  
Dynamics Simulation ◽  
Symmetric Pair ◽  
Dynamics Simulations

AbstractIn our molecular dynamics simulations of the system of identical particles interacting through the harmonic-repulsive pair potential, we observed the formation of a cubic crystal structure that belongs to theIa3̅d(#230) crystallographic space group. This crystal structure has not been previously seen either in experiments or in computer simulations, though its framework topology has been known from theoretical crystallographic considerations. Its unit cell contains 16 atoms, occupying only (16b) Wyckoff site, and arranged as two mutually intertwined unconnected networks with packing fraction of 0.37. The appearance of this structure is explained by the soft repulsive nature of the interaction potential. The observedIa3̅dstructure extends the small number of cubic structures formed in single component systems with spherically symmetric pair potentials in MD simulations. We speculate that materials with such structure could be found in soft matter systems or in selected crystals under high pressure.

A novel shift in the glass transition temperature of polymer nanocomposites: A molecular dynamics simulation study

2021 ◽  
Author(s):  
Raja Azhar Ashraaf Khan ◽  
Xian Chen ◽  
Hang-Kai Qi ◽  
Jian-Hua Huang ◽  
Meng-Bo Luo
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Molecular Dynamics Simulation ◽  
Polymer Nanocomposites ◽  
Simulation Study ◽  
Dynamics Simulation ◽  
Dynamics Simulations ◽  
System Volume

The effect of nanoparticles on the glass transition temperature, Tg, of polymer nanocomposites is studied by using molecular dynamics simulations. Tg is estimated from the variation of system volume with...

Multicanonical Molecular Dynamics Simulation Study of the Liquid-Solid and Solid-Solid Transitions in Lennard-Jones Clusters

2011 ◽  
Author(s):  
Toshihiro Kaneko ◽  
Kenji Yasuoka ◽  
Ayori Mitsutake ◽  
Xiao Cheng Zeng
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Transition Temperature ◽  
Peak Position ◽  
Temperature Curve ◽  
Dynamics Simulation ◽  
Lennard Jones ◽  
Dynamics Simulations ◽  
First Time ◽  
Good Agreement

Multicanonical molecular dynamics simulations are applied, for the first time, to study the liquid-solid and solid-solid transitions in Lennard-Jones (LJ) clusters. The transition temperatures are estimated based on the peak position in the heat capacity versus temperature curve. For LJ31, LJ58 and LJ98, our results on the solid-solid transition temperature are in good agreement with previous ones. For LJ309, the predicted liquid-solid transition temperature is also in agreement with previous result.

scholarly journals Reactive molecular dynamics simulation of the high-temperature pyrolysis of 2,2′,2′′,4,4′,4′′,6,6′,6′′-nonanitro-1,1′:3′,1′′-terphenyl (NONA)

RSC Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 5507-5515
Author(s):  
Liang Song ◽  
Feng-Qi Zhao ◽  
Si-Yu Xu ◽  
Xue-Hai Ju
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulation ◽  
Reactive Molecular Dynamics ◽  
Ring Compounds ◽  
Fused Ring ◽  
Dynamics Simulations

The bimolecular and fused ring compounds are found in the high-temperature pyrolysis of NONA using ReaxFF molecular dynamics simulations.

Molecular Dynamics Simulation Study of Lecithin Inhibiting Hydrate-Dissociation

2017 ◽  
Vol 890 ◽  
pp. 252-259
Author(s):  
Le Wang ◽  
Guan Cheng Jiang ◽  
Xin Lin ◽  
Xian Min Zhang ◽  
Qi Hui Jiang
Keyword(s):  
Molecular Dynamics ◽  
Water Movement ◽  
Simulation Analysis ◽  
Mass Density ◽  
Dynamics Simulation ◽  
Dissociation Process ◽  
Hydrate Dissociation ◽  
Hydrocarbon Chains ◽  
Dynamics Simulations ◽  
Mass Density Profile

Molecular dynamics simulations are used to study the dissociation inhibiting mechanism of lecithin for structure I hydrates. Adsorption characteristics of lecithin and PVP (poly (N-vinylpyrrolidine)) on the hydrate surfaces were performed in the NVT ensemble at temperatures of 277K and the hydrate dissociation process were simulated in the NPT ensemble at same temperature. The results show that hydrate surfaces with lecithin is more stable than the ones with PVP for the lower potential energy. The conformation of lecithin changes constantly after the balanced state is reached while the PVP molecular dose not. Lecithin molecule has interaction with lecithin nearby and hydrocarbon-chains of lecithin molecules will form a network to prevent the diffusion of water and methane molecules, which will narrow the available space for hydrate methane and water movement. Compared with PVP-hydrate simulation, analysis results (snapshots and mass density profile) of the dissociation simulations show that lecithin-hydrate dissociates more slowly.

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