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dc.contributor.authorJiménez Blas, Felipe 
dc.contributor.authorSanz, Eduardo
dc.contributor.authorVega, C.
dc.contributor.authorGalindo, Amparo
dc.identifier.issn1089-7690 (electrónico)
dc.description.abstractAn extension of Wertheim’s first-order thermodynamic perturbation theory is proposed to describe the global phase behavior of linear rigid tangent hard sphere chains. The extension is based on a scaling proposed recently by Vega and McBride [Phys. Rev. E 65, 052501 (2002)] for the equation of state of linear chains in the solid phase. We have used the Einstein-crystal methodology, the Rahman–Parrinello technique, and the thermodynamic integration method for calculating the free energy and equation of state of linear rigid hard sphere chains with different chain lengths, including the solid–fluid phase equilibria. Agreement between the simulation data and theoretical predictions is excellent in all cases. Once it is confirmed that the proposed theory can be used to describe correctly the equation of state, free energy, and solid–fluid phase transitions of linear rigid molecules, a simple mean-field approximation at the level of van der Waals is included to account for segment–segment attractive interactions. The approach is used to determine the global phase behavior of fully flexible and linear rigid chains of varying chain lengths. The main effect of increasing the chain length in the case of linear rigid chains is to decrease the fluid densities at freezing, so that the triple-point temperatures increase. As a consequence, the range of temperatures where vapor–liquid equilibria exist decreases considerably with chain length. This behavior is a direct result of the stabilization of the solid phase with respect to the liquid phase as the chain length is increased. The vapor–liquid equilibria are seen to disappear for linear rigid chains formed by more than 11 hard sphere segments that interact through an attractive van der Waals mean-field contribution; in other words, long linear rigid chains exhibit solid–vapor phase behavior only. In the case of flexible chains, the fluid–solid equilibrium is hardly affected by the chain length, so that the triple-point temperature reaches quickly an asymptotic value. In contrast to linear rigid chains, flexible chains present quite a broad range of temperatures where vapor–liquid equilibria exist. Although the vapor–liquid equilibria of flexible and linear rigid chain molecules are similar, the differences in the type of stable solid they form and, more importantly, the differences in the scaling of thermodynamic properties with chain length bring dramatic differences to the appearance of their phase diagrams.es_ES
dc.description.sponsorshipFinancial support is due to project Nos. BFM-2001- 1420-C02-01 and BFM-2001-1420-C02-02 of the Spanish DGICYT (Dirección General de Investigación Científica y Técnica). F.J.B. would like to acknowledge Universidad de Huelva and Junta de Andalucía for additional financial support. E.S. would like to thank the Ministerio de Educación y Cultura for the award of a PhD studentship (FPU). A.G. also thanks the Engineering and Physical Sciences Research Council for the award of an Advanced Research Fellowship.es_ES
dc.publisherAIP Publishinges_ES
dc.relation.isversionofPublisher’s versión
dc.rightsAtribución-NoComercial-SinDerivadas 3.0 España*
dc.subject.otherPhase equilibriaes_ES
dc.subject.otherLennard-Jones chainses_ES
dc.subject.otherWertheim's theoryes_ES
dc.subject.otherSolid phasees_ES
dc.subject.otherMolecular simulationes_ES
dc.subject.otherMonte Carloes_ES
dc.subject.otherFree energyes_ES
dc.subject.otherFlexible tangent chainses_ES
dc.subject.otherLinear rigid tangent chainses_ES
dc.titleFluid–solid equilibria of flexible and linear rigid tangent chains from Wertheim’s thermodynamic perturbation theoryes_ES

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