Evidence for single file diffusion of ethane in the molecular sieve AlPO4-5

Gupta, Vishwas; Nivarthi, Sriram S.; McCormick, Alon V.; Davis, H. T.

doi:10.1016/s0009-2614(95)01246-x

Cited by 155 publications

(122 citation statements)

References 20 publications

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“…0), Eq. (2) simplifies to lim t Wt 1 SqDt= p , with D the diffusion constant of a single particle, i.e., D const.…”

Section: P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

“…Since the sequence of particles in such a situation remains unaffected over time t, this leads to strong deviations from normal diffusion. One of the most striking features of SFD is that the mean-square displacement (MSD) Wt of a tracer particle for t much larger than the direct interaction time (i.e., the time a particle needs to move a significant fraction of the mean particle distance) is given by [1][2][3][4][5] …”

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confidence: 99%

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Single-File Diffusion of Colloids in One-Dimensional Channels

2004

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We study the diffusive behavior of colloidal particles which are confined to one-dimensional channels generated by scanning optical tweezers. At long times t, the mean-square displacement is found to scale as t 1=2 , which is expected for systems where single-file diffusion occurs. In addition, we experimentally obtain the long-time, self-diffusive behavior from the short-time collective density fluctuations of the system as suggested by a recent analytical approach [M. Kollmann, Phys. Rev. Lett. 90, 180602 (2003)]. DOI: 10.1103/PhysRevLett.93.026001 PACS numbers: 83.50.Ha, 82.70.Dd, 83.80.Hj Single-file diffusion (SFD), prevalent in many physical, chemical, and biological processes, refers to the onedimensional (1D) motion of interacting particles in pores which are so narrow that the mutual passage of particles is excluded. Since the sequence of particles in such a situation remains unaffected over time t, this leads to strong deviations from normal diffusion. One of the most striking features of SFD is that the mean-square displacement (MSD) Wt of a tracer particle for t much larger than the direct interaction time (i.e., the time a particle needs to move a significant fraction of the mean particle distance) is given by [1][2][3][4][5] where F is the SFD mobility. While most of the results for SFD are limited to hard-rod systems [6 -8], only recently has it been demonstrated by one of us that Eq. (1) remains valid for colloidal and atomic systems with arbitrary interaction potentials, provided the correlation length between the particles is of finite range and collisions are associated with some energy dissipation [9]. In addition, it was shown that the SFD mobility F can be determined by the compressibility and the short-time collective diffusion coefficient of the system. This is an interesting result, because it relates in a unique way a long-time feature, i.e., the SFD mobility to the short-time collective diffusional properties of the system. Although the asymptotic t 1=2 behavior of SFD systems was predicted almost 40 years ago, experimental studies of such non-Fickian diffusion processes were lacking for a long time. However, due to recent progress in the synthesis of zeolitic materials which consist of long quasicylindrical pores with diameters of several angstroms [10], experimentally accessible SFD systems are now available. By means of pulsed force gradient nuclear magnetic resonance (PFG-NMR) experiments, it was demonstrated that the transport of methane and ethane in such molecular sieves can indeed be described by SFD [2,3]. Experimental evidence for the occurrence of SFD as provided by different authors, however, remains contradictory [11]. In addition, some of the results obtained with PFG-NMR are not in agreement with recent quasielastic neutron scattering studies, which show that both methane and ethane exhibit normal diffusion in AlPO 4 molecular sieves [12]. Several possible reasons have been suggested to account for this discrepancy: First, due to almost inevitable deviations of the ...

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“…0), Eq. (2) simplifies to lim t Wt 1 SqDt= p , with D the diffusion constant of a single particle, i.e., D const.…”

Section: P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

mentioning

confidence: 99%

Single-File Diffusion of Colloids in One-Dimensional Channels

2004

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“…They showed that when the particles evolve according to Hamiltonian dynamics the mean squared displacement (MSD) of a tagged particle [also called tracer particle (TP)] grows diffusively, whereas for Brownian particles the MSD of a TP grows subdiffusively. Recently, several experiments have been able to observe TP diffusion by passive microrehology in zeolites, transport of colloidal particles or charged spheres in narrow circular channels [3][4][5][6][7][8][9]. Such experimental evidences have generated a great revival of interest in tagged particle diffusion.…”

Section: Introductionmentioning

confidence: 99%

Correlation and fluctuation in a random average process on an infinite line with a driven tracer

Cividini¹,

Kundu²,

Majumdar³

et al. 2016

J. Stat. Mech.

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We study the effect of single biased tracer particle in a bath of other particles performing the random average process (RAP) on an infinite line. We focus on the large time behavior of the mean and the fluctuations of the positions of the particles and also the correlations among them. In the large time t limit these quantities have well-defined scaling forms and grow with time as √ t. A differential equation for the scaling function associated with the correlation function is obtained and solved perturbatively around the solution for a symmetric tracer. Interestingly, when the tracer is totally asymmetric, further progress is enabled by the fact that the particles behind of the tracer do not affect the motion of the particles in front of it, which leads in particular to an exact expression for the variance of the position of the tracer. Finally, the variance and correlations of the gaps between successive particles are also studied. Numerical simulations support our analytical results.arXiv:1602.06689v1 [cond-mat.stat-mech]

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“…Nivarthi et al [27] and Gupta et al [28] have modelled the diffusion of methane and ethane, respectively, in AlPO 4 -5. Their results showed that the mean-square displacement of methane was proportional to the square root of time, an indication of single-file diffusion.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of the filling and decorating of carbon nanotubules

Mao¹,

Garg²,

1999

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Abstract. Carbon nanotubes (CNTs) have been proposed as excellent materials for the construction of new, precisely tailored ultrafiltration membranes and as promising fibres for the construction of new, stronger composite materials. In this paper classical molecular dynamics simulations are used to investigate the potential use of CNTs in these applications. Functional groups have been covalently attached to the walls of CNTs to provide more extensive interactions between these new fibres and a polymer matrix. We examine the effects of these attachments on the mechanical properties of the tubules. The diffusive molecular flow of methane, ethane and ethylene through single tubules at room temperature are also studied. The simulations predict normal-mode molecular diffusion for methane. However, diffusion that is intermediate between normal-mode and single-file diffusion is predicted for ethane and ethylene. These diffusion results are found to be similar to results predicted for molecular diffusion in zeolites.

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Evidence for single file diffusion of ethane in the molecular sieve AlPO4-5

Cited by 155 publications

References 20 publications

Single-File Diffusion of Colloids in One-Dimensional Channels

Single-File Diffusion of Colloids in One-Dimensional Channels

Correlation and fluctuation in a random average process on an infinite line with a driven tracer

Molecular dynamics simulations of the filling and decorating of carbon nanotubules

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