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dc.contributor.authorGloor, Guy J.
dc.contributor.authorJackson, George
dc.contributor.authorJiménez Blas, Felipe 
dc.contributor.authorMartín del Río, Elvira
dc.contributor.authorMiguel Agustino, Enrique de 
dc.date.accessioned2014-12-04T13:30:35Z
dc.date.available2014-12-04T13:30:35Z
dc.date.issued2004
dc.identifier.citationGloor, G.J., Jackson, G., Jiménez Blas, F., Martín del Río, E., Miguel Agustino, E.: "An accurate density functional theory for the vapor-liquid interface of associating chain molecules based on the statistical associating fluid theory for potentials of variable range". Journal of Chemical Physics. Vol. 121, n. 24, págs. 12740-12759, (2004). ISSN 0021-9606en_US
dc.identifier.issn0021-9606
dc.identifier.issn1089-7690 (electrónico)
dc.identifier.urihttp://hdl.handle.net/10272/9468
dc.description.abstractA Helmholtz free energydensity functional is developed to describe the vapor-liquid interface of associating chain molecules. The functional is based on the statistical associating fluid theory with attractive potentials of variable range (SAFT-VR) for the homogenous fluid [A. Gil-Villegas, A. Galindo, P. J. Whitehead, S. J. Mills, G. Jackson, and A. N. Burgess, J. Chem. Phys. 106, 4168 (1997)]. A standard perturbative density functional theory(DFT) is constructed by partitioning the free energy density into a reference term (which incorporates all of the short-range interactions, and is treated locally) and an attractive perturbation (which incorporates the long-range dispersion interactions). In our previous work [F. J. Blas, E. Martı́n del Rı́o, E. de Miguel, and G. Jackson, Mol. Phys. 99, 1851 (2001); G. J. Gloor, F. J. Blas, E. Martı́n del Rı́o, E. de Miguel, and G. Jackson, Fluid Phase Equil. 194, 521 (2002)] we used a mean-field version of the theory (SAFT-HS) in which the pair correlations were neglected in the attractive term. This provides only a qualitative description of the vapor-liquid interface, due to the inadequate mean-field treatment of the vapor-liquid equilibria. Two different approaches are used to include the correlations in the attractive term: in the first, the free energy of the homogeneous fluid is partitioned such that the effect of correlations are incorporated in the local reference term; in the second, a density averaged correlation function is incorporated into the perturbative term in a similar way to that proposed by Toxvaerd [S. Toxvaerd, J. Chem. Phys. 64, 2863 (1976)]. The latter is found to provide the most accurate description of the vapor-liquid surface tension on comparison with new simulation data for a square-well fluid of variable range. The SAFT-VR DFT is used to examine the effect of molecular chain length and association on the surface tension. Different association schemes (dimerization, straight and branched chain formation, and network structures) are examined separately. The surface tension of the associating fluid is found to be bounded between the nonassociating and fully associated limits (both of which correspond to equivalent nonassociating systems). The temperature dependence of the surface tension is found to depend strongly on the balance between the strength and range of the association, and on the particular association scheme. In the case of a system with a strong but very localized association interaction, the surface tension exhibits the characteristic “s shaped” behavior with temperature observed in fluids such as water and alkanols. The various types of curves observed in real substances can be reproduced by the theory. It is very gratifying that a DFT based on SAFT-VR free energy can provide an accurate quantitative description of the surface tension of both the model and experimental systems.en_US
dc.language.isoengen_US
dc.publisherAmerican Institute of Physicsen_US
dc.rightsAtribución-NoComercial-SinDerivadas 3.0 España*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/es/*
dc.titleAn accurate density functional theory for the vapor-liquid interface of associating chain molecules based on the statistical associating fluid theory for potentials of variable rangeen_US
dc.typeinfo:eu-repo/semantics/articleen_US
dc.relation.publisherversionhttp://scitation.aip.org/content/aip/journal/jcp/121/24/10.1063/1.1807833en_US
dc.identifier.doi10.1063/1.1807833
dc.rights.accessRightsinfo:eu-repo/semantics/openAccessen_US


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