Triple Point and Critical Point of Argon by Nose Constant Temperature Molecular Dynamics

Abstract

Triple point and critical point of argon were estimated by Nose constant temperature molecular dynamics. The slab model was assumed. The basic cell was tetragonal, where the central layer was FCC lattice at the initial stage. The number of molecules in the basic cell was 52488. The Lennard-Jones potential function was assumed. The pressure and potential energy were obtained as functions of temperature. The triple point was assigned by atomic configuration, potential energy and pressure. The critical point was assigned by the maximum point of fluctuation of the potential energy vs temperature plot. The estimated triple point temperature and pressure were reasonable compared with experimental data. The obtained critical temperature and pressure were reasonable compared with experimental data.