A Family of Tunable Spherically-Symmetric Potentials that Span the Range from Hard Spheres to Water-like Behavior

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dc.creatorYan, Zhenyu
dc.creatorBuldyrev, Sergey V.
dc.creatorGiovambattista, Nicolas
dc.creatorDebenedetti, Pablo G.
dc.creatorStanley, H. Eugene
dc.date2006-01-24
dc.date.accessioned2026-07-07T06:57:46Z
dc.date.available2026-07-07T06:57:46Z
dc.descriptionWe investigate the equation of state, diffusion coefficient, and structural order of a family of spherically-symmetric potentials consisting of a hard core and a linear repulsive ramp. This generic potential has two characteristic length scales: the hard and soft core diameters. The family of potentials is generated by varying their ratio, $λ$. We find negative thermal expansion (thermodynamic anomaly) and an increase of the diffusion coefficient upon isothermal compression (dynamic anomaly) for $0\leqλ<6/7$. As in water, the regions where these anomalies occur are nested domes in the ($T, ρ$) or ($T, P$) planes, with the thermodynamic anomaly dome contained entirely within the dynamic anomaly dome. We calculate translational and orientational order parameters ($t$ and $Q_6$), and project equilibrium state points onto the ($t, Q_6$) plane, or order map. The order map evolves from water-like behavior to hard-sphere-like behavior upon varying $λ$ between 4/7 and 6/7. Thus, we traverse the range of liquid behavior encompassed by hard spheres ($λ=1$) and water-like ($λ\sim4/7$) with a family of tunable spherically-symmetric potentials by simply varying the ratio of hard to soft-core diameters. Although dynamic and thermodynamic anomalies occur almost across the entire range $0\leqλ\leq1$, water-like structural anomalies (i.e., decrease in both $t$ and $Q_6$ upon compression and strictly correlated $t$ and $Q_6$ in the anomalous region) occur only around $λ=4/7$. Water-like anomalies in structure, dynamics and thermodynamics arise solely due to the existence of two length scales, orientation-dependent interactions being absent by design.
dc.descriptiontotal 21 pages, 6 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0601554
dc.identifierhttp://arxiv.org/abs/cond-mat/0601554
dc.identifierPhys. Rev. E 73, 051204 (2006)
dc.identifierdoi:10.1103/PhysRevE.73.051204
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/107094
dc.subjectSoft Condensed Matter
dc.titleA Family of Tunable Spherically-Symmetric Potentials that Span the Range from Hard Spheres to Water-like Behavior
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