Thermodynamic properties of hard ellipsoid square-well fluid

Singh, A. K.; Dey, Tarun Kumar; Sinha, S. K.

doi:10.1007/bf02847197

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…Singh et al used this last approach by dening a SW with an angular-dependent depth range. 20 It is also possible to dene a Janus SW ellipsoid by partial enclosure of the HE. 21 One of the most studied anisotropic pair potentials is the one given by Gay and Berne.…”

Section: Introductionmentioning

confidence: 99%

Towards understanding the empty liquid of colloidal platelets: vapour–liquid phase coexistence of square-well oblate ellipsoids

Meneses-Juárez

Varga²,

Orea

et al. 2013

Soft Matter

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We study the phase behaviour of hard oblate ellipsoids with superimposed short-ranged oblate-shaped square-well attractions using the replica exchange Monte Carlo method and a simple van der Waals type perturbation theory. By fixing the square-well range (l ¼ 0.25s k ), we examine the effect of varying the oblates aspect ratio, k ¼ s t /s k , on the density profiles, vapour-liquid and isotropic-nematic phase transitions. We observe that the formation of a liquid phase with vanishing density, an empty liquid, is possible with increasing aspect ratio. Surprisingly, the increasing shape anisotropy does not shift the stability region of the nematic phase to low densities, while the oblate-shaped square-well attraction favours disordered states. For k > 1.5, the critical temperature and packing fraction monotonically decrease with k, while the isotropic-nematic phase boundary moves towards higher packing fractions with decreasing temperature for all k. Simulations show that oblates preferably orientate their faces parallel to the vapour-liquid interface when located at the liquid side of the interface region and perpendicular when located at the vapour side.

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Section: Introductionmentioning

confidence: 99%

Towards understanding the empty liquid of colloidal platelets: vapour–liquid phase coexistence of square-well oblate ellipsoids

Meneses-Juárez

Varga²,

Orea

et al. 2013

Soft Matter

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“…If molecules are modeled as hard prolate ellipsoids, eqs. (A1)-(A6) should be slightly modified [60]. Being a and b = c the hard ellipsoid (HE) semi-axes, and χ o = a/b and…”

Section: Acknowledgmentsmentioning

confidence: 99%

Free energy and entropy of a dipolar liquid by computer simulations

Palomar

Sesé

2018

The Journal of Chemical Physics

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Thermodynamic properties for a system composed of dipolar molecules are computed. Free energy is evaluated by means of the thermodynamic integration technique, and it is also estimated by using a perturbation theory approach, in which every molecule is modeled as a hard sphere within a square well, with an electric dipole at its center. The hard sphere diameter, the range and depth of the well, and the dipole moment have been calculated from properties easily obtained in molecular dynamics simulations. Connection between entropy and dynamical properties is explored in the liquid and supercooled states by using instantaneous normal mode calculations. A model is proposed in order to analyze translation and rotation contributions to entropy separately. Both contributions decrease upon cooling, and a logarithmic correlation between excess entropy associated with translation and the corresponding proportion of imaginary frequency modes is encountered. Rosenfeld scaling law between reduced diffusion and excess entropy is tested, and the origin of its failure at low temperatures is investigated.

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“…At the level of the second virial perturbation, we first demonstrate that the liquid-vapor coexistence in the ΔB * 2 (T * )-η r plane yields a single master curve for all attractive shells and hardcores of a given size and shape, as shown in the following section. Since this does not guarantee the fulfillment of the corresponding states principle for short-range potentials, we then focus on a particular system of attractive anisotropic particles [4,[23][24][25][26][27]. That is, we studied the short-range behavior of oblates having a fixed anisotropy but variable square-well shapes and ranges for the attractive contribution.…”

Section: Introductionmentioning

confidence: 99%

Extended law of corresponding states: square-well oblates

Santiago

Gurin

Varga

et al. 2021

J. Phys.: Condens. Matter

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The vapour-liquid coexistence collapse in the reduced temperature, Tr=T/Tc, reduced density, ρr= ρ/ρc, plane is known as a principle of corresponding states, and Noro and Frenkel have extended it for pair potentials of variable range. Here, we provide a theoretical basis supporting this extension and show that it can also be applied to short-range pair potentials where both repulsive and attractive parts can be anisotropic. We observe that the binodals of oblate hard ellipsoids for a given aspect ratio (κ=1/3) with varying short-range square-well interactions collapse into a single master curve in the Δ B*2--ρr plane, where Δ B*2= (B2(T)-B*2(Tc))/v0, B2 is the second virial coefficient, and v0 is the volume of the hard body. This finding is confirmed by both REMC simulation and second virial perturbation theory for varying square-well shells, mimicking uniform, equator, and pole attractions. Our simulation results reveal that the extended law of corresponding states is not related to the local structure of the fluid.

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Thermodynamic properties of hard ellipsoid square-well fluid

Cited by 4 publications

References 10 publications

Towards understanding the empty liquid of colloidal platelets: vapour–liquid phase coexistence of square-well oblate ellipsoids

Towards understanding the empty liquid of colloidal platelets: vapour–liquid phase coexistence of square-well oblate ellipsoids

Free energy and entropy of a dipolar liquid by computer simulations

Extended law of corresponding states: square-well oblates

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