Issue
EPL
Volume 85, Number 3, February 2009
Article Number 36001
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/85/36001
Published online 10 February 2009
EPL, 85 (2009) 36001
DOI: 10.1209/0295-5075/85/36001

An ubiquitous mechanism for water-like anomalies

A. 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

oliveira@if.ufrgs.br

received 17 July 2008; accepted in final form 11 January 2009; published February 2009
published online 10 February 2009

Abstract
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, $\lambda$, from a ramp ($\lambda$ = 0.5) to a square-shoulder potential ($\lambda$ =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.

PACS
61.20.Ja - Computer simulation of liquid structure.
61.25.Em - Molecular liquids.
65.20.-w - Thermal properties of liquids.

© EPLA 2009