Mutual diffusion in a binary Ar-Kr mixture confined within zeolite NaY

Kamala, CR and Ayappa, KG and Yashonath, S (2002) Mutual diffusion in a binary Ar-Kr mixture confined within zeolite NaY. In: Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), 65 (5). 061202/1-12.

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Abstract

Molecular dynamics investigations of the mutual diffusion coefficients in an Ar-Kr mixture confined in the zeolite NaY are reported. Velocity auto- and cross correlations were computed at two different temperatures (200 and 600 K). The importance of the appropriate choice of reference frame while evaluating the time correlation functions is illustrated for argon in the zeolite NaY. Mutual diffusivities in the mixture were obtained in the barycentric reference frame. Recently, Zhou and Miller showed that the distinct diffusivity Dd is zero for the Ar-Kr mixture in bulk. On confinement, it is seen that at 200 K the ratio R=D11 /Ds=0.77, where D11 is the mutual diffusivity and Ds is the mixture self-diffusivity. However, at 600 K, R=0.97, implying that the contribution from distinct diffusion is only slightly negative. The large negative Dd at 200 K could be attributed to strong localization of Ar and Kr in the physisorption sites within the zeolite cages. Analysis of error bars and an efficient computational algorithm for evaluation of the velocity cross correlation function are also presented. The results have implications in biology, chemistry, and other situations where transport of confined mixtures is encountered.

Item Type:	Journal Article
Publication:	Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)
Publisher:	American Physical Society (APS)
Additional Information:	The DOI is currently only displayed. Copyright for this article belongs to American Physical Society (APS)
Department/Centre:	Division of Interdisciplinary Sciences > Supercomputer Education & Research Centre Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	21 Jul 2004
Last Modified:	19 Sep 2010 04:14
URI:	http://eprints.iisc.ac.in/id/eprint/1085

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