Deviations from the Normal Time Regime of Single-File Diffusion

Hahn, K.; Kärger, Jörg

doi:10.1021/jp981039h

Cited by 140 publications

(171 citation statements)

References 19 publications

(62 reference statements)

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“…These effects make it very difficult to determine single-file diffusion in experiments. 388 For example, for methane and ethane in AFI (AlPO 4 -5), some groups observe single-file diffusion 384,385 while others conclude normal diffusion. 387 Simulations have been used to investigate these controversies in detail.…”

Section: Single-file Diffusionmentioning

confidence: 99%

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

2008

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Section: Single-file Diffusionmentioning

confidence: 99%

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

2008

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“…where the diffusion coefficient has been replaced by a mobility factor, F x [6,7]. Single file diffusion occurs in a variety of natural and engineered systems, including ion and water transport through biological membranes [8][9][10][11], diffusion in molecular sieves such as zeolites [12][13][14], carbon nanotubes [15], * richard.bowles@usask.ca or metal organic frameworks [16,17], and charge-carrier diffusion in one dimensional channels [18].…”

Section: Introductionmentioning

confidence: 99%

Diffusion in quasi-one-dimensional channels: A small system n, p, T, transition state theory for hopping times

Ahmadi

Bowles

2017

The Journal of Chemical Physics

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Particles confined to a single file, in a narrow quasi-one dimensional channel, exhibit a dynamic crossover from single file diffusion to Fickian diffusion as the channel radius increases and the particles can begin to pass each other. The long time diffusion coefficient for a system in the crossover regime can be described in terms of a hopping time, which measures the time it takes for a particle to escape the cage formed by its neighbours. In this paper, we develop a transition state theory approach to the calculation of the hopping time, using the small system isobaric-isothermal ensemble to rigorously account for the volume fluctuations associated with the size of the cage. We also describe a Monte Carlo simulation scheme that can be used to calculate the free energy barrier for particle hopping. The theory and simulation method correctly predict the hopping times for a two dimensional confined ideal gas system and a system of confined hard discs over a range of channel radii, but the method breaks down for wide channels in the hard discs case, underestimating the height of the hopping barrier due to the neglect of interactions between the small system and its surroundings.

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“…In addition, MD studies 52 have suggested that when molecules have the ability to pass each other in the nanopore, small changes in the system can have a significant effect on the results, which further complicates the characterization of transition-mode diffusion. Temperature also has been shown to play a role in determining the diffusion mode, 53 where higher temperatures allow molecules that might normally not be able to, to squeeze past one another.…”

mentioning

confidence: 99%

A Computational Study of Molecular Diffusion and Dynamic Flow through Carbon Nanotubes

2000

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Molecular dynamics simulations are used to study the flow of methane, ethane, and ethylene through carbon nanotubes at room temperature. The interatomic forces in the simulations are calculated using a classical, reactive, empirical bond-order hydrocarbon potential coupled to Lennard-Jones potentials. The simulations show that the intermolecular and molecule-nanotube interactions strongly affect both dynamic molecular flow and molecular diffusion. For example, molecules with initial hyperthermal velocities slowed to thermal velocities in nanotubes with diameters less than 36 Å. In addition, molecules moving at thermal velocities are predicted to diffuse from areas of high density to areas of low density through the nanotubes. Normalmode molecular thermal diffusion is predicted for methane for nearly all the nanotube diameters considered. In contrast, ethane and ethylene are predicted to diffuse by normal mode, single-file mode, or at a rate that is transitional between normal-mode and single-file diffusion over the time scales considered in the simulations, depending on the diameter of the nanotube. When the nanotube diameters are between 16 and 22 Å, ethane and ethylene are predicted to follow a helical diffusion path that depends on the helical symmetry of the nanotube. The effects of atomic termination at the nanotube opening and pore-pore interactions within a nanotube bundle on the diffusion results are also considered.

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Deviations from the Normal Time Regime of Single-File Diffusion

Cited by 140 publications

References 19 publications

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

Diffusion in quasi-one-dimensional channels: A small system n, p, T, transition state theory for hopping times

A Computational Study of Molecular Diffusion and Dynamic Flow through Carbon Nanotubes

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