We report a computer-simulation study of the equilibrium phase diagram of a three-dimensional system of particles with a repulsive-shoulder potential. The phase diagram was obtained using free-energy calculations. At low temperatures, we observe a number of distinct crystal phases. We show that at certain values of the potential parameters the system exhibits the waterlike thermodynamic anomalies: a density anomaly and a diffusion anomaly. The anomalies disappear with increasing the repulsive step width: more precisely, their locations move to the region where the crystalline phase is stable.

Phys. Rev. E

Gribova, N. V., Fomin, Y. D., Frenkel, D., & Ryzhov, V. N. (2009). Waterlike thermodynamic anomalies in a repulsive-shoulder potential system. Phys. Rev. E, 79(Article number: 51202), 1–6. doi:10.1103/physreve.79.051202