A simple one-dimensional lattice model with water-like phase behaviour

6 pags, 4 figsWe analyse the phase behaviour of a simple one-dimensional lattice model with two repulsive ranges (a hard core repulsion that covers two sites and a next-to-nearest neighbour repulsive interaction), a long-ranged staggered mean field, and an additional mean field attraction. The model is investigated in terms of its analytic solution. By a suitable choice of the next-to-nearest neighbour repulsive interaction and the mean field attraction, the model displays a phase behaviour closely connected with that of water: a solid phase less dense than its fluid counterpart, a solid that melts upon isothermal compression, and no stable liquid-liquid equilibrium.The authors acknowledge support from the Dirección General de Investigación Científica y Técnica under grant no. MAT2007-65711-C04-04 and the Dirección General de Universidades e Investigación de la Comunidad de Madrid under Grant S0505/ESP/0299, program MOSSNOHO-CM. They are also most grateful for the hospitality of the Institut for Fysikk, NTNU (Tronhdeim, Norway) where this work was conceived and partly carried out