Polymorphism, thermodynamic anomalies and network formation in an   atomistic model with two internal states
  Using molecular dynamics simulations we study the temperature-density phase diagram of a simple model system of particles in two dimensions. In addition to translational degrees of freedom, each particle has two internal states and interacts with a modified Lennard-Jones potential which depends on relative positions as well as the internal states. We find that, despite its simplicity, the model has a rich phase diagram showing many features of common network-forming liquids such as water and silica, including polymorphism and thermodynamic anomalies. We believe our model may be useful for studies concerning generic features of such complex liquids. 
Chandana Mondal and Surajit Sengupta (I.A.C.S., Kolkata)
cond-mat.soft