Anomalous Phase Diagrams in the Simplest Plasma Models
  Remarkable feature of new first-order phase transitions of gas-liquid gas-crystal types in combination with traditional solid-liquid transition are under consideration in a modified one-component plasma model (OCP) with uniform, but compressible background. Structure and parameters of this phase transition strongly depend on the value of charge number Z. Under high values of Z the model shows remarkable and completely unusual topology of phase diagram. 
Igor L. Iosilevski, Alexander Yu. Chigvintsev