MOLECULAR-DYNAMICS SIMULATION OF THE ORTHOBARIC DENSITIES AND SURFACE-TENSION OF WATER

Molecular dynamics simulations have been performed to study the liquid-vapor equilibrium of water as a function of temperature. The orthobaric densities and the surface tension of water are reported for temperatures from 316 K until 573 K. The extended simple point charge (SPC/E) interaction potential for water molecules is used with full Ewald summation. The normal and tangential components of the pressure tensor were calculated and are presented at 328 K. The nature of the long-range contribution to the surface tension has been studied in detail. At 328 K the calculated surface tension is 66.0±3.0 mN m-1 in comparison with the experimental value of 67 mN m-1. The simulated surface tensions between 316 K and 573 K are in good agreement with experiment. The orthobaric densities are in better agreement with experimental values than those obtained from the Gibbs ensemble calculation for the SPC model of water. © 1995 American Institute of Physics.