Molecular Dynamics Study of the Self-Diffusion of Ions in B2O3Melt at High Pressure

2001 ◽  
Vol 105 (34) ◽  
pp. 7973-7978 ◽  
Author(s):  
Jason Diefenbacher ◽  
Paul F. McMillan
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
The Self ◽  
Self Diffusion

Self-diffusion of lignite/water under different temperatures and pressure: A molecular dynamics study

2016 ◽  
Vol 30 (01) ◽  
pp. 1550253 ◽  
Author(s):  
Xinjian Liu ◽  
Yu Jin ◽  
Congliang Huang ◽  
Jingfeng He ◽  
Zhonghao Rao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Water System ◽  
Simulation Method ◽  
The Self ◽  
Dynamics Simulation ◽  
Low Rank ◽  
Self Diffusion ◽  
Change Mechanism ◽  
Different Temperatures ◽  
Temperature And Pressure

Temperature and pressure have direct and remarkable implications for drying and dewatering effect of low rank coals such as lignite. To understand the microenergy change mechanism of lignite, the molecular dynamics simulation method was performed to study the self-diffusion of lignite/water under different temperatures and pressure. The results showed that high temperature and high pressure can promote the diffusion of lignite/water system, which facilitates the drying and dewatering of lignite. The volume and density of lignite/water system will increase and decrease with temperature increasing, respectively. Though the pressure within simulation range can make lignite density increase, the increasing pressure showed a weak impact on variation of density.

Molecular-Dynamics Analysis of the Structural Properties of Silica during Cooling

2008 ◽  
Vol 139 ◽  
pp. 101-106 ◽  
Author(s):  
Byoung Min Lee ◽  
Shinji Munetoh ◽  
Teruaki Motooka ◽  
Yeo Wan Yun ◽  
Kyu Mann Lee
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Transition Temperature ◽  
Structural Properties ◽  
Diffusion Coefficients ◽  
The Self ◽  
Dynamics Analysis ◽  
Self Diffusion ◽  
Dynamics Simulations ◽  
Potential Parameters

The structural properties of SiO2 liquid during cooling have been investigated by molecular dynamics simulations. The interatomic forces acting on the particles are calculated by the modified Tersoff potential parameters. The glass transition temperature and structural properties of the resulting SiO2 system at various temperatures have been investigated. The fivefold coordinations of Si and threefold coordinations of O atoms were observed, and the coordination defects of system decrease with decreasing temperature up to 17 % at 300 K. The self-diffusion coefficients for Si and O atoms drop to almost zero below 3000 K. The structures were distorted at high temperatures, but very stable atomic network persisted up to high temperature in the liquid state.

scholarly journals Evidence for Glass Behavior in Amorphous Carbon

2020 ◽  
Vol 6 (3) ◽  
pp. 50 ◽  
Author(s):  
Steven Best ◽  
Jake B. Wasley ◽  
Carla de Tomas ◽  
Alireza Aghajamali ◽  
Irene Suarez-Martinez ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Glass Transition ◽  
Transition Temperature ◽  
Amorphous Carbon ◽  
The Self ◽  
Self Diffusion ◽  
Dynamics Simulations ◽  
Self Diffusion Coefficient ◽  
Glass Behavior

Amorphous carbons are disordered carbons with densities of circa 1.9–3.1 g/cc and a mixture of sp2 and sp3 hybridization. Using molecular dynamics simulations, we simulate diffusion in amorphous carbons at different densities and temperatures to investigate the transition between amorphous carbon and the liquid state. Arrhenius plots of the self-diffusion coefficient clearly demonstrate that there is a glass transition rather than a melting point. We consider five common carbon potentials (Tersoff, REBO-II, AIREBO, ReaxFF and EDIP) and all exhibit a glass transition. Although the glass-transition temperature (Tg) is not significantly affected by density, the choice of potential can vary Tg by up to 40%. Our results suggest that amorphous carbon should be interpreted as a glass rather than a solid.

A Molecular Dynamics Simulation of Molten (Li-Rb)Cl Implying the Chemla Effect of Mobilities

1980 ◽  
Vol 35 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Isao Okada ◽  
Ryuzo Takagi ◽  
Kazutaka Kawamura
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Diffusion Coefficients ◽  
Strong Correlation ◽  
Pair Correlation ◽  
The Self ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Pure Salt ◽  
Dynamics Simulations

Abstract A new transport property, the self-exchange velocity (SEV) of neighbouring unlike ions, has been evaluated from molecular dynamics simulations of molten LiCl, RbCl and LiRbCl2 at 1100 K and the mixture at 750 K. From the increase of the SEV's in the order Rb+ (pure salt) <Li+ (mixture) < Rb+ (mixture) < Li+ (pure salt), it is conjectured that there is a strong correlation between the SEV’s and the internal mobilities. An interpretation of the Chemla effect in its dependence on temperature is given. The pair correlation functions and the self-diffusion coefficients are also calculated and discussed.

scholarly journals Molecular-Dynamics Simulation of Self-Diffusion of Molecular Hydrogen in X-Type Zeolite

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoming Du
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Hydrogen Diffusion ◽  
Mean Free Path ◽  
The Self ◽  
Dynamics Simulation ◽  
Pulse Field ◽  
Self Diffusion ◽  
Hydrogen Molecules ◽  
Dynamics Simulations

The self-diffusion of hydrogen in NaX zeolite has been studied by molecular-dynamics simulations for various temperatures and pressures. The results indicate that in the temperature range of 77–293 K and the pressure range of 10–2700 kPa, the self-diffusion coefficients are found to range from 1.61 × 10−9 m2·s−1to 3.66 × 10−8 m2·s−1which are in good agreement with the experimental values from the quasielastic neutron scattering (QENS) and pulse field gradients nuclear magnetic resonance (PFG NMR) measurements. The self-diffusion coefficients decrease with increasing pressure due to packing of sorbate-sorbate molecules which causes frequent collusion among hydrogen molecules in pores and increase with increasing temperature because increasing the kinetic energy of the gas molecules enlarges the mean free path of gas molecule. The activated energy for hydrogen diffusion determined from the simulation is pressure-dependent.

A Molecular Dynamics Simulation of the Transport Properties of Molten (La1/3, K)Cl

2005 ◽  
Vol 60 (3) ◽  
pp. 187-192 ◽  
Author(s):  
Masahiko Matsumiya ◽  
Koichi Seo
Keyword(s):  
Molecular Dynamics ◽  
Charge Asymmetry ◽  
The Self ◽  
Dynamics Simulation ◽  
Alkali Chloride ◽  
Self Diffusion ◽  
Dynamical Properties ◽  
Experimental Values ◽  
Dynamics Simulations ◽  
Self Diffusion Coefficient

Molecular dynamics simulations of molten (La1/3, K)Cl at 1123 K have been performed in order to investigate the correlation between simulated dynamical properties such as the self-exchange velocity (ν), the self-diffusion coefficient (D) and the electrical conductivity (κ) and the corresponding experimental values. The simulated results revealed that v and D of potassium decrease with increasing mole fraction of lanthanum, as expected from the experimental internal cation mobilities, b. The decrease of bK, νK and DK is ascribed to the tranquilization effect by La3+, which strongly interacts with Cl−. In contrast, bLa, νLa, and DLa increase with increasing concentration of La3+. The distorted linkage of the network structure of [LaCl6]3− units was disconnected with increasing the concentration of the alkali chloride. This might be attributed to the stronger association of La3+ with Cl− due to the enhanced charge asymmetry of the two cations neighboring Cl−. The sequence of the calculated v’s, D’s, and κ’s is consistent with those of the referred experimental results.

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