Prediction of the PVT properties of water over wide range of temperatures and pressures from molecular dynamics simulation

In this study, we systematically performed a series of isothermal-isobaric molecular dynamics simulations over a wide range of temperatures and pressures to evaluate the pressure-volume-temperature (PVT) properties of water with four popular molecular potential, SPCE, TIP4P, TIP5P and EP. From the overview of the simulated data and their comparisons with experimental data, we find that SPCE shows overall better predictions than the other three models, slightly better than TIP4P, but far more accurate than EP and TIP5P. Compared with the most recent published high-pressure experimental data up to 5.0 GPa, the simulation results with SPCE show remarkable agreement with errors less than 1.0%. Considering this potential was proposed based on very few experimental data under room temperatures and pressures, the high accuracy of the simulation results indicate a great predictive power of molecular level study and verify our attempt of using molecular dynamics simulations to generate data as an important supplement to the database of experimental properties of geological fluids. Based on our simulated data of SPCE and experimental data, a new equation of state (EOS) was proposed with better accuracy for the volumetric properties of liquid than previous models from 100.0 MPa and 273.15 K up to substantial ionization limit, which is about 20-30 GPa and 2000 K according to previous studies. (c) 2004 Elsevier B.V. All rights reserved.