Do the repulsive and attractive pair forces play separate roles for the physics of liquids?

Bøhling, Lasse; Veldhorst, Arno A.; Ingebrigtsen, Trond S.; Bailey, Nicholas P.; Hansen, Jesper S.; Toxværd, Søren; Schrøder, Thomas B.; Dyre, Jeppe C.

doi:10.1088/0953-8984/25/3/032101

Cited by 34 publications

(45 citation statements)

References 24 publications

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“…Even if other states, in particular much closer to the glass transition, should be investigated to provide wider evidence, we preliminarily conclude that the fast mobility in a mildly-supercooled molecular liquid is not driven by the force exerted by the closest neighbours. Notice that iso-mobility and iso-relaxation time states of an atomic liquid, with equal density and temperature, exhibit identical local force distributions P (F ), and then equal MSF [112]. This different behaviour needs further investigation.…”

Section: Fast Mobility and Local Forcesmentioning

confidence: 94%

“…Our present results point to the conclusion that the local geometry correlates poorly with the fast mobility. In order to understand if, in spite of the minor role of the cage geometry, states with identical fast mobility exhibit common aspects of the total force acting on a particle, we investigated the distribution of the modulus P (F ) [112]. In particular, we are interested in the mean square force (MSF) F 2 which includes both binary and triplet force contributions [113].…”

Section: Fast Mobility and Local Forcesmentioning

confidence: 99%

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Weak links between fast mobility and local structure in molecular and atomic liquids

Bernini

Puosi

Leporini

2015

The Journal of Chemical Physics

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We investigate by Molecular-Dynamics simulations the fast mobility -the rattling amplitude of the particles temporarily trapped by the cage of the neighbors -in mildly supercooled states of dense molecular (linear trimers) and atomic (binary mixtures) liquids. The mixture particles interact by the Lennard-Jones potential. The non-bonded particles of the molecular system are coupled by the more general Mie potential with variable repulsive and attractive exponents in a range which is characteristic of small n-alkanes and n-alcohols. Possible links between the fast mobility and the geometry of the cage (size and shape) are searched. The correlations on a per-particle basis are rather weak. Instead, if one groups either the particles in fast-mobility subsets or the cages in geometric subsets, the increase of the fast mobility with both the size and the asphericity of the cage is revealed. The observed correlations are weak and differ in states with equal relaxation time. Local forces between a tagged particle and the first-neighbour shell do not correlate with the fast mobility in the molecular liquid. It is concluded that the cage geometry alone is unable to provide a microscopic interpretation of the known, universal link between the fast mobility and the slow structural relaxation. We suggest that the particle fast dynamics is affected by regions beyond the first neighbours, thus supporting the presence of collective, extended fast modes.

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Section: Fast Mobility and Local Forcesmentioning

confidence: 94%

Section: Fast Mobility and Local Forcesmentioning

confidence: 99%

Weak links between fast mobility and local structure in molecular and atomic liquids

Bernini

Puosi

Leporini

2015

The Journal of Chemical Physics

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“…This so-called power-law density-scaling relation was established by Alba-Simionesco and coworkers, as well as by Roland, Paluch, and coworkers, for many van der Waals bonded organic liquids and polymers [50][51][52][53]. For large density changes the density-scaling exponent is not constant and a more general form of scaling takes over [50,54,55], which is the one used below.…”

mentioning

confidence: 85%

Density scaling and quasiuniversality of flow-event statistics for athermal plastic flows

2014

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Athermal plastic flows were simulated for the Kob-Andersen binary Lennard-Jones system and its repulsive version in which the sign of the attractive terms is changed to a plus. Properties evaluated from simulations at different densities include the distributions of energy drops, stress drops, and strain intervals between the flow events. By reference to hidden scale invariance we show that simulations at a single density in conjunction with an equilibrium-liquid simulation at the same density allows one to predict the plastic flow-event properties at other densities. We furthermore demonstrate quasiuniversality of the flow-event statistics.

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“…In all these cases the theory was checked by tracing out isomorphs in the thermodynamic phase diagram and testing for the predicted invariants. The methods used for generating isomorphs in simulation have been detailed elsewhere [27,37].…”

Section: B Isomorphsmentioning

confidence: 99%

Isomorphs, hidden scale invariance, and quasiuniversality

Dyre

2013

Phys. Rev. E

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This paper first establishes an approximate scaling property of the potential-energy function of a classical liquid with good isomorphs (a Roskilde-simple liquid). This "pseudohomogeneous" property makes explicit that -and in which sense -such a system has a hidden scale invariance. The second part gives a potential-energy formulation of the quasiuniversality of monatomic Roskilde-simple liquids, which was recently rationalized in terms of the existence of a quasiuniversal single-parameter family of reduced-coordinate constant-potential-energy hypersurfaces [J. C. Dyre, Phys. Rev. E 87, 022106 (2013)]. The new formulation involves a quasiuniversal reduced-coordinate potential-energy function. A few consequences of this are discussed.

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Do the repulsive and attractive pair forces play separate roles for the physics of liquids?

Cited by 34 publications

References 24 publications

Weak links between fast mobility and local structure in molecular and atomic liquids

Weak links between fast mobility and local structure in molecular and atomic liquids

Density scaling and quasiuniversality of flow-event statistics for athermal plastic flows

Isomorphs, hidden scale invariance, and quasiuniversality

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