Phase Diagram of Hard Ellipsoids of Revolution

Abstract

We present the results of Monte Carlo simulations of the equation of state of hard ellipsoids of revolution with axial ratio's a/b = 3, 2.75, 2, 1.25, 0.8, 0.5, 0.3636 and 0.3333. We identify four distinct phases, viz. isotropic fluid, nematic fluid, ordered solid and plastic solid. In all cases the thermodynamic phase transitions are located by free energy computation. We find nematic phases only for a/b ≥ 2.75 and a/b ≤ 1/2.75. A plastic solid phase is observed for 1.25 ≥ a/b / 0.8. It is found that the phase diagram is surprisingly symmetric under interchange of the major and minor axes of the ellipsoids.