Calculation of the Melting Entropy of Argon at Constant Volume Using Molecular Dynamics

Abstract

The melting entropy values of argon at constant volume (Δ_vS) as a function of density were calculated using molecular dynamics simulations. These calculations employed cells with N = 864 molecules. The resulting entropy of melting per particle, Δ_vS/N, was found to be essentially constant (with some slight effect of the crystal form) and nearly equal to 0.5 k, where k is the Boltzmann constant. The melting entropy values at constant pressure (Δ_pS) were also determined and it was observed that Δ_pS > Δ_vS. In addition, variations in the vibrational frequency in the liquid were compared with fluctuations in the solid near the melting point as a means of further investigating the melting entropy.