Perturbation Correction for the Free Energy and Structure of Simple Fluids

Section: Application To a Polymer Modelmentioning

confidence: 99%

Equation of state and critical behavior of polymer models: A quantitative comparison between Wertheim’s thermodynamic perturbation theory and computer simulations

MacDowell

Mueller

Vega

et al. 2000

“…Moreover, the latter put forward the ansatz of the universality of the bridge function, namely that the main features of the bridge function are largely independent of the chosen reference system. The preceding approaches took on various acronyms, such as RHNC, 1 MHNC, 2 VMHNC, 3 or variations thereof. These were extended to multicomponent systems by Enciso et al 4 and González et al 5 More recently Rosenfeld 6,7 has introduced a selfconsistent fundamental measure free-energy density functional that provides simple expressions for the bridge functional.…”

Section: Introductionmentioning

confidence: 99%

The bridge functions of molten salts

Taşseven

González

Silbert

et al. 2001

The bridge functions of molten NaCl and AgI near melting were obtained by using the model potentials of Born-Huggins-Mayer for NaCl and Vashishta-Rahman for AgI. The calculations of the bridge functions involved molecular dynamics simulations, the extension of the procedure originally proposed by Poll et al. ͓Phys. Rev. A 37, 1672 ͑1988͔͒ and the numerical solution of the Ornstein-Zernike equations. The calculated bridge functions do not conform with the universality ansatz. They also differ from the bridge functions obtained for model electrolytes. Following the results obtained for electrolytes and those of this work for molten salts, it is conjectured that the universality ansatz for the bridge functions does not apply for systems whose attractive interactions play a decisive role in their structural ordering.

“…[17][18][19][20][21] Approaches based more on first principles include a perturbation method, which approximates b͑r͒ of the potential of interest using a simpler short-ranged potential. [22][23][24][25] Another route to obtain b͑r͒ is a direct evaluation in terms of the bridge-function coefficients defined by the density expansion of the function…”

Section: ͑1͒mentioning

confidence: 99%

Evaluation of bridge-function diagrams via Mayer-sampling Monte Carlo simulation

Kwak

Kofke

2005

We report coefficients of the h-bond expansion of the bridge function of the hard-sphere system up to order ρ4 (where ρ is the density in units of the hard-sphere diameter), which in the highest-order term includes 88 cluster diagrams with bonds representing the total correlation function h(r). Calculations are performed using the recently introduced Mayer-sampling method for evaluation of cluster integrals, and an iterative scheme is applied in which the h(r) used in the cluster integrals is determined by solution of the Ornstein–Zernike equation with a closure given by the calculated clusters. Calculations are performed for reduced densities from 0.1 to 0.9 in increments of 0.1. Comparison with molecular simulation data shows that the convergence is very slow for the density expansion of the bridge function calculated this way.