Comparative investigations of the P–V–T relationship of NaCl at high pressure and temperature

摘要

Two different potential models of molecular dynamics (MD) simulations have been applied to investigate the pressure–volume–temperature (P–V–T) relationship and lattice parameter of NaCl under high pressure and temperature. The first one is the shell model (SM) potentials in which due to the short-range interaction pairs of ions are moved together as is the case in polarization of a crystal due to the motion of the positive and negative ions, and the second one is the two-body rigid-ion Born–Mayer–Huggins–Fumi–Tosi (BMHFT) potentials with full treatment of long-range Coulomb forces. The P–V relationship at 300 K, T–V relationship at zero pressure, and lattice parameter a, have been obtained and compared with the available experimental data and other theoretical results. Compared with SM potentials, the MD simulation with BMHFT potentials is very successful in reproducing accurately the measured volumes of NaCl. At an extended pressure and temperature ranges, P–V relationship under different isotherms at selected temperatures, T–V relationship under different pressures, and lattice parameter a have also been predicted. The properties of NaCl are summarized in the pressure range 0–30 GPa and the temperature up to 2000 K.