Predicting the density-scaling exponent of a glass-forming liquid from Prigogine–Defay ratio measurements

Gundermann, Ditte; Pedersen, Ulf R.; Hecksher, Tina; Bailey, Nicholas P.; Jakobsen, Bo; Christensen, Tage Emil; Olsen, Niels Boye; Schrøder, Thomas B.; Fragiadakis, D.; Casalini, R.; Roland, C. M.; Dyre, Jeppe C.; Niss, Kristine

doi:10.1038/nphys2031

Cited by 131 publications

(119 citation statements)

References 47 publications

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…This theory has been tested successfully experimentally [12] and numerically [13][14][15]. In all cases studied so far in detail the systems were in equilibrium, however.…”

Section: Introductionmentioning

confidence: 89%

Isomorph invariance of Couette shear flows simulated by the SLLOD equations of motion

Separdar

Bailey²,

Schrøder³

et al. 2013

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Non-equilibrium molecular dynamics simulations were performed to study the thermodynamic, structural, and dynamical properties of the single-component Lennard-Jones and the Kob-Andersen binary Lennard-Jones liquids. Both systems are known to have strong correlations between equilibrium thermal fluctuations of virial and potential energy. Such systems have good isomorphs (curves in the thermodynamic phase diagram along which structural, dynamical, and some thermodynamic quantities are invariant when expressed in reduced units). The SLLOD equations of motion were used to simulate Couette shear flows of the two systems. We show analytically that these equations are isomorph invariant provided the reduced strain rate is fixed along the isomorph. Since isomorph invariance is generally only approximate, a range of shear rates were simulated to test for the predicted invariance, covering both the linear and non-linear regimes. For both systems, when represented in reduced units the radial distribution function and the intermediate scattering function are identical for state points that are isomorphic. The strain-rate dependence of the viscosity, which exhibits shear thinning, is also invariant along an isomorph. Our results extend the isomorph concept to the non-equilibrium situation of a shear flow, in which the phase diagram is three dimensional because the shear rate defines a third dimension.

show abstract

“…This theory has been tested successfully experimentally [12] and numerically [13][14][15]. In all cases studied so far in detail the systems were in equilibrium, however.…”

Section: Introductionmentioning

confidence: 89%

Isomorph invariance of Couette shear flows simulated by the SLLOD equations of motion

Separdar

Bailey²,

Schrøder³

et al. 2013

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, while we previously suggested that ionic liquids are not Roskilde simple, it seems likely that such systems with not too strong Coulomb forces, e.g., room-temperature ionic liquids, may well be so. In experiment, glass-forming Roskilde-simple liquids are characterized by a Prigogine-Defay ratio close to unity [31,39]; moreover, such liquids obey density scaling and isochronal superposition [21], which are characteristic features of van der Waals liquids.…”

Section: B Isomorphsmentioning

confidence: 99%

“…Extensive computer simulations have shown [15,[17][18][19][20][21][25][26][27][28][29][30], however, that the predicted isomorph invariants apply to a good approximation for a wide variety of systems. A few experimental predictions of the isomorph theory have been confirmed, as well [29,31,32]. This paper first discusses the case of general Roskilde-simple liquids, including mixtures [21,28,30] and molecular systems [17].…”

Section: Introductionmentioning

confidence: 99%

Isomorphs, hidden scale invariance, and quasiuniversality

Dyre

2013

Phys. Rev. E

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…A limitation of using the correlation of W and U as a means to classify liquids is the difficulty in experimentally assessing this correlation (although recently it was shown that the proportionality constant between fluctuations in W and U can be calculated from linear thermoviscoelastic data for a single state point [42]). However, the expectation that certain properties are integral to correlating liquids implies that the latter can be identified by adherence to these properties.…”

Section: Density Scalingmentioning

confidence: 99%

Are polar liquids less simple?

Fragiadakis

Roland

2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

Strong correlation between equilibrium fluctuations of the potential energy, U, and the virial, W, is a characteristic of a liquid that implies the presence of certain dynamic properties, such as density scaling of the relaxation times and isochronal superpositioning of the relaxation function. In this work we employ molecular dynamics simulations (mds) on methanol and two variations, lacking hydrogen bonds and a dipole moment, to assess the connection between the correlation of U and W and these dynamic properties. We show, in accord with prior results of others [T. S. Ingebrigtsen, T.B. Schrøder, J.C. Dyre, Phys. Rev. X 2, 011011 (2012).], that simple van der Waals liquids exhibit both strong correlations and the expected dynamic behavior. However, for polar liquids this correspondence breaks down -weaker correlation between U and W is not associated with worse conformance to density scaling or isochronal superpositioning. The reason for this is that strong correlation between U and W only requires their proportionality, whereas the expected dynamic behavior depends primarily on constancy of the proportionality constant for all state points. For hydrogen-bonded liquids, neither strong correlation nor adherence to the dynamic properties is observed; however, this nonconformance is not directly related to the concentration of hydrogen bonds, but rather to the greater deviation of the intermolecular potential from an inverse power law (IPL). Only (hypothetical) liquids having interactions governed strictly by an IPL are perfectly correlating and exhibit the consequent dynamic properties over all thermodynamic conditions.

show abstract

Predicting the density-scaling exponent of a glass-forming liquid from Prigogine–Defay ratio measurements

Cited by 131 publications

References 47 publications

Isomorph invariance of Couette shear flows simulated by the SLLOD equations of motion

Isomorph invariance of Couette shear flows simulated by the SLLOD equations of motion

Isomorphs, hidden scale invariance, and quasiuniversality

Are polar liquids less simple?

Contact Info

Product

Resources

About