An Equation of State for the Self-Diffusion Coefficient in Lennard–Jones Fluid Derived by Molecular Dynamics Simulations

Kataoka, Yosuke; Fujita, Minoru

doi:10.1246/bcsj.68.152

Cited by 11 publications

(2 citation statements)

References 11 publications

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“…The self-part of the dynamic structure factor is approximated to be purely diffusive, where D means the self-diffusion coefficient of the solute. We neglect the critical anomaly of the self-diffusion coefficient, because it is quite small if any. , …”

Section: Resultsmentioning

confidence: 99%

Study of Nonpolar Solvation Dynamics in Supercritical Lennard−Jones Fluids in Terms of the Solvent Dynamic Structure Factor

2002

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The nonpolar solvation dynamics in Lennard−Jones fluids is discussed in terms of the relationship with the dynamic structure factor of neat solvent, using the theoretical expression that describes the solvation correlation function as the superposition of solvent dynamic structure factors at various wavenumbers. Several expressions for the coupling strength between the state transition of the solute and the solvent density modes are examined with respect to their abilities to predict the static fluctuation. In the present theoretical model, it is found that the difference between the ground- and excited-state solute−solvent interactions can be adequately taken as the coupling strength with the solvent density mode. Employing this expression for the coupling, the solvent fluctuation around k ≅ σ -1 (σ stands for the diameter of the solvent) contributes dominantly to the static fluctuation in all the densities investigated. This corresponds to the feature of the solvation dynamics in mixed solvents, in which the effective wavenumber is determined to be 1.14σ-1 from the proportionality between the solvation rates and the diffusion coefficients in the higher-density region. The half decay time (t 1/2) of the dynamic structure factor at this wavenumber shows similar density dependence to that of the solvation correlation function obtained in our previous work. The half decay time of the dynamic structure factor is correlated with the static structure factor. This supports our previous proposal that the curvature of the free energy surface along the solvation coordinate is essential to the solvation dynamics. The agreement between the present theory and the simulation is further improved by taking the motion of the solute into account.

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Section: Resultsmentioning

confidence: 99%

Study of Nonpolar Solvation Dynamics in Supercritical Lennard−Jones Fluids in Terms of the Solvent Dynamic Structure Factor

2002

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“…The diffusion coefficient has been intensively studied in theories based on non-equilibrium statistical physics. [7,8] Molecular dynamic (MD) simulation is another powerful tool for the study of dynamic processes in the liquid phase and the self-diffusion processes in neat liquids have also been simulated. [9,10] To calculate the transport properties of simple and molecular fluids, non-equilibrium molecular dynamics (NEMD) simulations have also emerged as a powerful tool.…”

Section: Introductionmentioning

confidence: 99%

Critical anomaly and finite size scaling of the self-diffusion coefficient for Lennard—Jones fluids by non-equilibrium molecular dynamic simulation

Asad

2011

Chinese Phys. B

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We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard-Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with temperature decreases by increasing density. For density ρ * = ρσ 3 = 0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T * = kT /ε = 1.25. The value of the self-diffusion coefficient strongly depends on system size. The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments. This correction scales as N −α , where α is an adjustable parameter and N is the number of particles. It is observed that the values of α < 1 provide quite a good correction to the simulation data. The system size dependence is very strong for lower densities, but it is not as strong for higher densities. The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations from the literature.

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Solution Structure in Supercritical Fluids

Arai

Sako

Takebayashi

2002

Supercritical Fluids

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An Equation of State for the Self-Diffusion Coefficient in Lennard–Jones Fluid Derived by Molecular Dynamics Simulations

Cited by 11 publications

References 11 publications

Study of Nonpolar Solvation Dynamics in Supercritical Lennard−Jones Fluids in Terms of the Solvent Dynamic Structure Factor

Study of Nonpolar Solvation Dynamics in Supercritical Lennard−Jones Fluids in Terms of the Solvent Dynamic Structure Factor

Critical anomaly and finite size scaling of the self-diffusion coefficient for Lennard—Jones fluids by non-equilibrium molecular dynamic simulation

Solution Structure in Supercritical Fluids

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