Publications (2)6.67 Total impact
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Article: Structural anomalies for a three dimensional isotropic core-softened potential.
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ABSTRACT: Using molecular dynamics simulations we investigate the structure of a system of particles interacting through a continuous core-softened interparticle potential. We found for the translational order parameter t a local maximum at a density rho(t-max) and a local minimum at rho(t-min)>rho(t-max). Between rho(t-max) and rho(t-min), the t parameter anomalously decreases upon increasing pressure. For the orientational order parameter Q(6) a maximum was observed at a density rho(t-max)<rho(Qmax)<rho(t-min). For densities between rho(Qmax) and rho(t-min), both the translational (t) and orientational (Q(6)) order parameters have anomalous behavior. We know that this system also exhibits density and diffusion anomalies. We found that the region in the pressure-temperature phase diagram of the structural anomaly englobes the region of the diffusion anomaly that is larger than the region limited by the temperature of maximum density. This cascade of anomalies (structural, dynamic, and thermodynamic) for our model has the same hierarchy as that observed for the simple point charge/extended water.The Journal of Chemical Physics 09/2006; 125(12):124503. · 3.33 Impact Factor -
Article: Thermodynamic and dynamic anomalies for a three-dimensional isotropic core-softened potential.
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ABSTRACT: Using molecular-dynamics simulations and integral equations (Rogers-Young, Percus-Yevick, and hypernetted chain closures) we investigate the thermodynamics of particles interacting with continuous core-softened intermolecular potential. Dynamic properties are also analyzed by the simulations. We show that, for a chosen shape of the potential, the density, at constant pressure, has a maximum for a certain temperature. The line of temperatures of maximum density (TMD) was determined in the pressure-temperature phase diagram. Similarly the diffusion constant at a constant temperature, D, has a maximum at a density rho(max) and a minimum at a density rho(min) < rho(max). In the pressure-temperature phase diagram the line of extrema in diffusivity is outside of the TMD line. Although this interparticle potential lacks directionality, this is the same behavior observed in simple point charge/extended water.The Journal of Chemical Physics 03/2006; 124(8):084505. · 3.33 Impact Factor
