Massively Parallel Molecular Dynamics Simulation of Gas Permeation across Molecular Sieving Porous Membranes

1996 ◽  
Vol 464 ◽  
Author(s):  
Phillip I. Pohl ◽  
Grant S. Heffelfinger
Keyword(s):  
Molecular Dynamics ◽  
Chemical Potential ◽  
Control Volume ◽  
Sol Gel ◽  
Gas Permeation ◽  
Dynamics Simulation ◽  
Massively Parallel ◽  
Solid Models ◽  
Parallel Supercomputers ◽  
Molecular Sieving

AbstractIn this work we simulate the diffusion of gases in a microporous solid models using a newly developed dual control volume grand canonical molecular dynamics technique. This allows spatial variation of chemical potential and hence an accurate simulation of steady-state pressure driven diffusion. The molecular sieving nature of microporous zeolites are discussed and compared with that for amorphous silica from sol-gel methods. Massively parallel supercomputers allow a quick and insightful study of these microporous structures.

Molecular Dynamics Computer Simulations of Diffusion in Porous Silicates

1994 ◽  
Vol 366 ◽  
Author(s):  
Grant S. Heffelfinger ◽  
Phillip I. Pohl ◽  
Laura J. D. Frink
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Chemical Potential ◽  
Control Volume ◽  
Dual Control ◽  
Cylindrical Pore ◽  
Knudsen Effect ◽  
State Pressure ◽  
Molecular Sieving ◽  
Grand Canonical

ABSTRACTIn this work a newly developed dual control volume grand canonical molecular dynamics technique simulates the diffusion of gas in a cylindrical pore. This allows spatial variation of chemical potential and hence an accurate simulation of steady state pressure driven diffusion. The molecular sieving nature of imicroporous imogolite models and the Knudsen effect are discussed and compared with experimental data.

scholarly journals Mass Transfer through Vapour–liquid Interfaces: a Molecular Dynamics Simulation Study

2021 ◽  
Author(s):  
Simon Stephan ◽  
Dominik Schäfer ◽  
Kai Langenbach ◽  
Hans Hasse
Keyword(s):  
Molecular Dynamics ◽  
Mass Transfer ◽  
Molecular Dynamics Simulation ◽  
Mass Flux ◽  
Chemical Potential ◽  
Control Volume ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Liquid Interfaces ◽  
Simulation Volume

A quasi-stationary molecular dynamics simulation method for studying mass transfer through vapour–liquid interfaces of mixtures driven by gradients of the chemical potential based on the dual control volume (DCV) method is described and tested. The rectangular simulation volume contains three bulk domains: a liquid domain in the middle with vapour on each side such that there are two vapour–liquid interfaces. The mass flux is generated by prescribing the chemical potential in control volumes in the vapour domains close to the outer boundary of the simulation volume. The simulation method was applied for studies of two binary Lennard-Jones mixtures: one in which a strong enrichment of the low-boiling component at the vapour–liquid interface is observed and another in which there is practically no enrichment. The two mixtures differ only in the dispersive interactions; their bulk diffusion coefficients are similar. Furthermore, the prescribed chemical potential difference was the same in all simulations. Nevertheless, important differences in the mass flux of the low-boiling component were observed for the two mixtures at all studied temperatures which might be related to the enrichment at the interfaces.

Gradient-Driven Diffusion Using Dual Control Volume Grand Canonical Molecular Dynamics (DCV-GCMD)

1995 ◽  
Vol 408 ◽  
Author(s):  
Frank Van Swol ◽  
Grant S. Heffelfinger
Keyword(s):  
Molecular Dynamics ◽  
Chemical Potential ◽  
Control Volume ◽  
Simulation Method ◽  
Steady State Mode ◽  
Transient Phenomena ◽  
Insertion And Deletion ◽  
Separate Control ◽  
Control Volumes ◽  
Grand Canonical

AbstractRecently we developed a new nonequilibrium molecular simulation method [1] that allows the direct study of interdiffusion in multicomponent mixtures. The method combines stochastic insertion and deletion moves characteristic of grand canonical (GC) simulations with molecular dynamics (MD) to control the chemical potential μi of a species i. Restricting the insertions and deletions to two separate control volumes (CV's) one can apply different μ's in distinct locations, and thus create chemical potential gradients. DCV-GCMD can be used to study transient phenomena such as the filling of micropores or used in steady-state mode to determine the diffusion coefficients in multicomponent fluid mixtures. We report on the effects of molecular interactions and demonstrate how in a sufficiently nonideal ternary mixture this can lead to up-hill or reverse diffusion. In addition we introduce a novel extension of DCV-GCMD that is specifically designed for the study of gradient-driven diffusion of molecules that are simply too large to be inserted and deleted.

Estimation of the Chemical Potential and the Activity of NaCl in Molten DyCl3-NaCl by Molecular Dynamics Simulation

1998 ◽  
Vol 53 (8) ◽  
pp. 655-658
Author(s):  
Masanori Sakurai ◽  
Ryuzo Takagi ◽  
Ashok K. Adyaa ◽  
Marcelle Gaune-Escard
Keyword(s):  
Molecular Dynamics ◽  
Phase Diagram ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Chemical Potential ◽  
Dynamics Simulation ◽  
Dynamics Simulations ◽  
Positional Data ◽  
Liquidus Temperatures

Abstract Molecular dynamics simulations of molten DyCl3-NaCl were carried out at liquidus temperatures of the phase diagram. The chemical potential and the activity of NaCl was successfully estimated with the method proposed by Powles et al., which requires only positional data of the ions at the temperatures in question.

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