Thermodynamic and structural anomalies of the Gaussian-core model in one dimension

Speranza, Cristina; Prestipino, Santi; Giaquinta, P. V.

doi:10.1080/00268976.2011.628342

Cited by 19 publications

(33 citation statements)

References 36 publications

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“…Moreover, the center of the attractive well is displaced from the repulsive core in order that the strength of the repulsion be roughly unaffected by the attraction. This makes it possible to compare the phase behavior of the system investigated here with that of the popular Gaussian-core model (GCM) fluid [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Twofold reentrant melting in a double-Gaussian fluid

Prestipino

Speranza

Malescio

et al. 2014

The Journal of Chemical Physics

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Isotropic pair potentials that are bounded at the origin have been proposed from time to time as models of the effective interaction between macromolecules of interest in the chemical physics of soft matter. We present a thorough study of the phase behavior of point particles interacting through a potential which combines a bounded short-range repulsion with a much weaker attraction at moderate distances, both of Gaussian shape. Notwithstanding the fact that the attraction acts as a small perturbation of the Gaussian-core model potential, the phase diagram of the doubleGaussian model (DGM) is far richer, showing two fluid phases and four distinct solid phases in the case that we have studied. Using free-energy calculations, the various regions of confluence of three distinct phases in the DGM system have all been characterized in detail. Moreover, two distinct lines of reentrant melting are found, and for each of them a rationale is provided in terms of the elastic properties of the solid phases.

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Section: Introductionmentioning

confidence: 99%

Twofold reentrant melting in a double-Gaussian fluid

Prestipino

Speranza

Malescio

et al. 2014

The Journal of Chemical Physics

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“…In the past few decades, isotropic pair potentials with two repulsive scales were the leading paradigm for understanding water at a simplified level, especially with regard to its many thermodynamic, structural, and dynamic anomalies [4,5,[22][23][24][25][26]. However, it is worth recalling that anomalies are also observed in the phase behavior of particles interacting through a one-scale bounded potential like the GCM potential [27][28][29].…”

Section: Resultsmentioning

confidence: 99%

Phase behavior of a fluid with a double Gaussian potential displaying waterlike features

et al. 2014

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Pair potentials that are bounded at the origin provide an accurate description of the effective interaction for many systems of dissolved soft macromolecules (e.g., flexible dendrimers). Using numerical free-energy calculations, we reconstruct the equilibrium phase diagram of a system of particles interacting through a potential that brings together a Gaussian repulsion with a much weaker Gaussian attraction, close to the thermodynamic stability threshold. Compared to the purely repulsive model, only the reentrant branch of the melting line survives, since for lower densities solidification is overridden by liquid-vapor separation. As a result, the phase diagram of the system recalls that of water up to moderate (i.e., a few tens of MPa) pressures. Upon superimposing a suitable hard core on the double-Gaussian potential, a further transition to a more compact solid phase is induced at high pressure, which might be regarded as the analog of the ice I-to-ice III transition in water.

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“…[38][39][40][41] These analytic results provide insight into more realistic systems in higher dimensions. The equation of state for the HR system was solved exactly by Tonks 42 and thus, this system is colloquially known as a Tonks gas.…”

Section: Introductionmentioning

confidence: 87%

Stochastic dynamics of penetrable rods in one dimension: Entangled dynamics and transport properties

Craven

Popov

Hernandez

2015

The Journal of Chemical Physics

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The dynamical properties of a system of soft rods governed by stochastic hard collisions (SHCs) have been determined over a varying range of softness using molecular dynamics simulations in one dimension and analytic theory. The SHC model allows for interpenetration of the system's constituent particles in the simulations, generating overlapping clustering behavior analogous to the spatial structures observed in systems governed by deterministic bounded potentials. Through variation of an assigned softness parameter δ, the limiting ranges of intermolecular softness are bridged, connecting the limiting ensemble behavior from hard to ideal (completely soft). Various dynamical and structural observables are measured from simulation and compared to developed theoretical values. The spatial properties are found to be well predicted by theories developed for the deterministic penetrable-sphere model with a transformation from energetic to probabilistic arguments. While the overlapping spatial structures are complex, the dynamical properties can be adequately approximated through a theory built on impulsive interactions with Enskog corrections. Our theory suggests that as the softness of interaction is varied toward the ideal limit, correlated collision processes are less important to the energy transfer mechanism, and Markovian processes dominate the evolution of the configuration space ensemble. For interaction softness close to hard limit, collision processes are highly correlated and overlapping spatial configurations give rise to entanglement of single-particle trajectories.

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Thermodynamic and structural anomalies of the Gaussian-core model in one dimension

Cited by 19 publications

References 36 publications

Twofold reentrant melting in a double-Gaussian fluid

Twofold reentrant melting in a double-Gaussian fluid

Phase behavior of a fluid with a double Gaussian potential displaying waterlike features

Stochastic dynamics of penetrable rods in one dimension: Entangled dynamics and transport properties

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