An ubiquitous mechanism for water-like anomaliesA. B. de Oliveira1, P. A. Netz2 and M. C. Barbosa1
1 Universidade Federal do Rio Grande do Sul, Instituto de Física - 91501-970, Porto Alegre, RS, Brazil
2 Universidade Federal do Rio Grande do Sul, Instituto de Química - 91501-970, Porto Alegre, RS, Brazil
received 17 July 2008; accepted in final form 11 January 2009; published February 2009
published online 10 February 2009
Using collision-driven molecular dynamics a system of spherical particles interacting through an effective two-length-scales potential is studied. The potential can be tuned by means of a single parameter, , from a ramp ( = 0.5) to a square-shoulder potential ( =1.0) representing a family of two-length-scales potentials in which the shortest interaction distance has higher potential energy than the largest interaction distance. For all the potentials, ranging between the ramp and the square-shoulder, density and structural anomalies were found, while the diffusion anomaly is found in all but in the square-shoulder potential. The presence of anomalies in square-shoulder potential, not observed in previous simulations, confirms the assumption that the two-length-scales potential is an ubiquitous ingredient for a system to exhibit water-like anomalies.
61.20.Ja - Computer simulation of liquid structure.
61.25.Em - Molecular liquids.
65.20.-w - Thermal properties of liquids.
© EPLA 2009