Effective isotropic potential for dipolar hard spheres

Teixeira, Paulo Ivo Cortez

doi:10.1088/0953-8984/25/19/195102

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…11,67 From a computational point of view, short-range many-body interactions could be easier to treat than long-range two-body interactions, in some situations. To this end, the two-body interaction potential can be developed in a number of ways beyond the leadingorder term used in this work, [33][34][35][36][37][38][39][40]45 and the three-body Axilrod-Teller potential can be retained as the chain-forming interaction. The prospect of moving to four-body interactions is not appealing.…”

Section: Discussionmentioning

confidence: 99%

“…[33][34][35][36][37][38][39][40] If the RDF is available, 41 then one can seek a unique density-dependent effective pair potential 42 by using iterative Boltzmann inversion starting from the potential of mean force −k B T ln g(r), 43,44 or by inverting the Ornstein-Zernike equation. 45 A different approach is taken here, based on a model system with two-body −r −6 attractions and three-body AT interactions -with the aforementioned temperature-dependent coefficientscomplemented by a soft-sphere repulsion. This is a simple system that should behave like a simple fluid at high temperature (where the two-body interaction dominates) and exhibit particle chaining at low temperature (where the three-body interaction dominates).…”

Section: Introductionmentioning

confidence: 99%

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Simulations of dipolar fluids using effective many-body isotropic interactions

Sindt

Camp

2015

The Journal of Chemical Physics

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The partition function of a system with pairwise-additive anisotropic dipole-dipole interactions is equal to that of a hypothetical system with many-body isotropic interactions [G. Stell, Phys. Rev. Lett. 32, 286 (1974)]. The effective many-body interactions contain n-body contributions of all orders. Each contribution is known as an expansion in terms of the particle-particle distances r, and the coefficients are temperature dependent. The leading-order two-body term is the familiar −r −6 attraction, and the leading-order three-body term is equivalent to the Axilrod-Teller interaction. In this work, a fluid of particles with the leading-order two-body and three-body interactions is compared to an equivalent dipolar soft-sphere fluid. Molecular simulations are used to determine the conditions under which the effective many-body interactions reproduce the fluid-phase structures of the dipolar system. The effective many-body interaction works well at moderately high temperatures, but fails at low temperatures where particle chaining is expected to occur. It is shown that an adjustment of the coefficients of the two-body and three-body terms leads to a good description of the structure of the dipolar fluid even in the chaining regime, due primarily to the ground-state linear configuration of the three-body Axilrod-Teller interaction. The vapor-liquid phase diagrams of systems with different Axilrod-Teller contributions are determined. As the strength of the three-body interaction is increased, the critical temperature and density both decrease, and disappear completely above a threshold strength, where chaining eventually suppresses the condensation transition.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulations of dipolar fluids using effective many-body isotropic interactions

Sindt

Camp

2015

The Journal of Chemical Physics

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“…Further, using inverse Fourier transform one obtains the PDF g(r) which describes the average probability of finding a particle at a given distance r from the other [3]. The PDF allows one to determine the reological, electromagnetic, and thermodynamic characteristics of ferrofluids [4,5]. However, the analysis of experimental SF data to reconstruct the PDF is very sensitive to the basic model of a ferrofluid chosen to interpret the experimental data.…”

Section: Introductionmentioning

confidence: 99%

Structure Properties in a Bidisperse Ferrofluid in the Absence of an External Magnetic Field

Nekhoroshkova

Elfimova

2015

SSP

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The structure properties of a ferrofluid modeled by a bidisperse system of dipolar hardspheres are studied theoretically for the case of zero external field. Analytical expressions are providedfor the pair distribution function (PDF) and structure factor (SF) to within the first order in numberdensity and the second order in dipole-dipole interaction strength. The influence of the granulometriccomposition on the behavior of the PDF and the position of the first peak of the SF is analyzed.

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