Atomistic Simulation of Shock Wave-Induced Melting in Argon.

A three-dimensional molecular dynamics simulation of shock wave loading was undertaken to investigate the Hugoniot equation of state at the transition of argon from solid to liquid. The simulated data agree with shock wave and static high-pressure experimental data. The melting transition in this simulation occurs without overshooting the argon melting temperature. There are two discontinuities that may bracket a mixed-phase region of solid and liquid along the simulated argon Hugoniot. This is an intrinsic feature of the Hugoniot crossing the argon melting curve and does not require the addition of any solid-solid phase transition.