title: Using compressibility factor as a predictor of confined hard-sphere fluid dynamics.
abstract: We study the correlations between the diffusivity (or viscosity) and the compressibility factor of bulk hard-sphere fluid as predicted by the ultralocal limit of the barrier hopping theory. Our specific aim is to determine if these correlations observed in the bulk equilibrium hard-sphere fluid can be used to predict the self-diffusivity of fluid confined between a slit-pore or a rectangular channel. In this work, we consider a single-component and a binary mixture of hard spheres. To represent confining walls, we use purely reflecting hard walls and interacting square-well walls. Our results clearly show that the correspondence between the diffusivity and the compressibility factor can be used along with the knowledge of the confined fluid's compressibility factor to predict its diffusivity with quantitative accuracy. Our analysis also suggests that a simple measure, the average fluid density, can be an accurate predictor of confined fluid diffusivity for very tight confinements ( approximately 2-3 particle diameters wide) at low to intermediate density conditions. Together, these results provide further support for the idea that one can use robust connections between thermodynamic and dynamic quantities to predict dynamics of confined fluids from their thermodynamics.
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA. jeetain@helix.nih.gov
authors.forename: Jeetain
authors.initials: J
authors.lastname: Mittal
mesh_terms: D000465:Algorithms; D004058:Diffusion; D008956:Models, Chemical; D011312:Pressure; D013816:Thermodynamics
references.citation: J Phys Chem B. 2005 Dec 15;109(49):23237-49
references.pmid: 16375288
references.citation: J Chem Phys. 2007 Oct 21;127(15):154513
references.pmid: 17949179
references.citation: Phys Rev Lett. 2006 May 5;96(17):177804
references.pmid: 16712334
references.citation: Phys Rev Lett. 2008 Apr 11;100(14):145901
references.pmid: 18518049
references.citation: Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Jul;62(1 Pt B):993-1001
references.pmid: 11088556
references.citation: J Chem Phys. 2005 Oct 22;123(16):164103
references.pmid: 16268677
references.citation: J Chem Phys. 2007 Oct 28;127(16):164505
references.pmid: 17979358
references.citation: J Chem Phys. 2007 Jun 28;126(24):244708
references.pmid: 17614578
references.citation: J Phys Chem B. 2007 Aug 30;111(34):10054-63
references.pmid: 17629320
references.citation: Nature. 2002 Apr 25;416(6883):811-5
references.pmid: 11976674
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Dec;80(6 Pt 1):061205
references.pmid: 20365159
references.citation: J Chem Phys. 2007 Oct 28;127(16):164506
references.pmid: 17979359
references.citation: J Phys Chem B. 2006 Sep 21;110(37):18147-50
references.pmid: 16970429
references.citation: J Phys Condens Matter. 2006 Jul 19;18(28):L371-8
references.pmid: 21690830
references.citation: Proc Natl Acad Sci U S A. 2006 Jan 17;103(3):529-31
references.pmid: 16407150
references.citation: J Chem Phys. 2006 Aug 21;125(7):076102
references.pmid: 16942382
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Mar;65(3 Pt 1):032501
references.pmid: 11909127
references.citation: Phys Rev Lett. 2008 Mar 14;100(10):106001
references.pmid: 18352209