Direct correlation functions and bridge functions in additive hard-sphere mixtures
Por:
Yuste S.B., Santos A., De Haro M.L.
Publicada:
1 ene 2002
Resumen:
A method to obtain (approximate) analytical expressions for the radial distribution functions in a multicomponent mixture of additive hard spheres that was recently introduced is used to obtain the direct correlation functions and bridge functions in these systems. This method, which yields results practically equivalent to the generalized mean spherical approximation and includes thermodynamic consistency, is an alternative to the usual integral equation approaches and requires as input only the contact values of the radial distribution functions and the isothermal compressibility. Calculations of the bridge functions for a binary mixture using the Boublík-Mansoori-Carnahan-Starling-Leland equation of state are compared to parallel results obtained from the solution of the Percus-Yevick equation. We find that the conjecture recently proposed by Guzmán and del Río (1998, Molec., 95, 645), stating that the zeros of the bridge functions occur approximately at the same value of the shifted distance for all pairs of interactions, is at odds with our results. Moreover, in the case of disparate sizes, even the Percus-Yevick bridge functions do not have this property. It is also found that the bridge functions are not necessarily non-positive.
Filiaciones:
Yuste S.B.:
Departamento de Física, Universidad de Extremadura, E-06071 Badajoz, Spain
Santos A.:
Departamento de Física, Universidad de Extremadura, E-06071 Badajoz, Spain
De Haro M.L.:
Centro de Investigación en Energía, UNAM, Temixco, Mor. 62580, Mexico
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