A Molecular Dynamics Simulation of the Molten Ternary System (Li, K, Cs)Cl

2000 ◽  
Vol 55 (11-12) ◽  
pp. 856-860 ◽  
Author(s):  
Masahiko Matsumiya ◽  
Ryuzo Takagi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Ternary System ◽  
Diffusion Coefficients ◽  
Pair Correlation ◽  
The Self ◽  
Dynamics Simulation ◽  
Eutectic System ◽  
Self Diffusion ◽  
Dynamics Simulations

The self-exchange velocity (SEV) of neighboring unlike ions, has been evaluated by molecular dynamics simulations of molten CsCl, (Li, K)C1 and (Li, K, Cs)Cl at 673 K. From the increase of the SEV's in the same order as the internal mobilities it is conjectured that there is a strong correlation between these two properties. The pair correlation functions, and the self-diffusion coefficients and the SEV's of Li+, K+, and Cs+ with reference to Cl- have also been calculated. The results allow to conclude that the self-exchange velocity of the cations become vCs < vK < vLi at xCs =0.1 and vLi < vK < vCs at xCs > 0.4. The sequence of the self-diffusion coefficients agrees with that of the SEV's. The results enable to conclude that it is possible to enrich Cs at up to xCs ~ 0.3 - 0.4 in the molten LiCl-KCl eutectic system.

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.

scholarly journals Estimation of the Enrichment of Cs in Molten Chloride and Fluoride Systems by Molecular Dynamics Simulation

2001 ◽  
Vol 56 (3-4) ◽  
pp. 279-287 ◽  
Author(s):  
Masahiko Matsumiya ◽  
Ryuzo Takagi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Diffusion Coefficients ◽  
The Self ◽  
Dynamics Simulation ◽  
Molten Chloride ◽  
Self Diffusion ◽  
Metallic Fuels ◽  
Relative Differences ◽  
Pyrochemical Reprocessing

Abstract For the pyrochemical reprocessing of spent metallic fuels in molten salt baths it is of importance to estimate the enrichment degree of Cs. A molecular dynamics simulation has been executed on molten (Li, Na, Cs)Cl at 900 K and (Li, Na, Cs)F at 925 K for various compositions in order to calculate the relative differences in the internal cation mobilities of Cs in molten LiCl-NaCl equimolar mixtures and the LiF-NaF eutectic. According to these results the self-exchange velocities of Li+, Na+ and Cs+ with respect to Cl- and F- have similar tendencies at each composition, and Cs can be enriched effectively up to xCs = 0.5 -0.6 in LiCl-NaCl melts. In addition, the sequence of the calculated self-diffusion coefficients for various compositions was in a fair agreement with that of the obtained self-exchange velocities.

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.

Molecular dynamics simulation of self-diffusion coefficients for liquid metals

2013 ◽  
Vol 22 (8) ◽  
pp. 083101 ◽  
Author(s):  
Yuan-Yuan Ju ◽  
Qing-Ming Zhang ◽  
Zi-Zheng Gong ◽  
Guang-Fu Ji
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Diffusion Coefficients ◽  
Liquid Metals ◽  
Dynamics Simulation ◽  
Self Diffusion

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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