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Title: The standard mean-field treatment of inter-particle attraction in classical DFT is better than one might expect
Authors: Archer, Andrew J.
Chacko, Blesson
Evans, Robert
Keywords: cond-mat.soft
cond-mat.stat-mech
Issue Date: 2017
Publisher: AIP © The Authors
Citation: ARCHER, A.J., CHACK, B. and EVANS, R., 2017. The standard mean-field treatment of inter-particle attraction in classical DFT is better than one might expect. Journal of Chemical Physics, 147 (3), 034501.
Abstract: In classical density functional theory (DFT) the part of the Helmholtz free energy functional arising from attractive inter-particle interactions is often treated in a mean-field or van der Waals approximation. On the face of it, this is a somewhat crude treatment as the resulting functional generates the simple random phase approximation (RPA) for the bulk fluid pair direct correlation function. We explain why using standard mean-field DFT to describe inhomogeneous fluid structure and thermodynamics is more accurate than one might expect based on this observation. By considering the pair correlation function $g(x)$ and structure factor $S(k)$ of a one-dimensional model fluid, for which exact results are available, we show that the mean-field DFT, employed within the test-particle procedure, yields results much superior to those from the RPA closure of the bulk Ornstein-Zernike equation. We argue that one should not judge the quality of a DFT based solely on the approximation it generates for the bulk pair direct correlation function.
Description: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in ARCHER, A.J., CHACK, B. and EVANS, R., 2017. The standard mean-field treatment of inter-particle attraction in classical DFT is better than one might expect. Journal of Chemical Physics, 147 (3), 034501 and may be found at http://dx.doi.org/10.1063/1.4993175.
Sponsor: B.C. is supported by an EPSRC studentship and R.E. by a Leverhulme Emeritus Fellowship: EM-2016-031.
Version: Accepted for publication
DOI: 10.1063/1.4993175
URI: https://dspace.lboro.ac.uk/2134/25857
Publisher Link: http://dx.doi.org/10.1063/1.4993175
ISSN: 0021-9606
Appears in Collections:Published Articles (Maths)

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