RT Journal Article
T1 First-principles derivation of density-functional formalism for quenched-annealed systems
A1 Lafuente, Luis
A1 Cuesta, José A.
AB We derive from first principles (without resorting to the replica trick) a density-functional theory for fluids in quenched disordered matrices (QA-DFT). We show that the disorder-averaged free energy of the fluid is a functional of the average density profile of the fluid as well as the pair correlation of the fluid and matrix particles. For practical reasons it is preferable to use another functional: the disorder-averaged free energy plus the fluid-matrix interaction energy, which, for fixed fluid-matrix interaction potential, is a functional only of the average density profile of the fluid. When the matrix is created as a quenched configuration of another fluid, the functional can be regarded as depending on the density profile of the matrix fluid as well. In this situation, the replica Ornstein-Zernike equations which do not contain the blocking parts of the correlations can be obtained as functional identities in this formalism, provided the second derivative of this functional is interpreted as the connected part of the direct correlation function. The blocking correlations are totally absent from QA-DFT, but nevertheless the thermodynamics can be entirely obtained from the functional. We apply the formalism to obtain the exact functional for an ideal fluid in an arbitrary matrix, and discuss possible approximations for nonideal fluids.
PB The American Physical Society
SN 1539-3755
YR 2006
FD 2006-10
LK https://hdl.handle.net/10016/7210
UL https://hdl.handle.net/10016/7210
LA eng
NO 9 pages, no figures.-- PACS nrs.: 61.20.Gy, 64.10.+h, 61.43.Gt, 31.15.Ew.-- ArXiv pre-print available at: http://arxiv.org/abs/cond-mat/0606689
NO Final publisher version available Open Access at: http://gisc.uc3m.es/~cuesta/papers-year.html
NO MR#: MR2283981
NO This work is part of project No. BFM2003-0180from Ministerio de Ciencia y Tecnología (Spain), of project No. UC3M-FI-05-007 from Universidad Carlos III de Madrid and Comunidad Autónoma de Madrid (Spain), and of project MOSSNOHO (No. S-0505/ESP/000299) from Comunidad Autónoma de Madrid (Spain).
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