Molecular Dynamic Simulations of Strontium Chloride Nanoparticle Nucleation in Supercritical Water

Abstract

The nucleation kinetics for strontium chloride nanoparticles in supercritical water is studied by molecular dynamic simulations. The thermodynamic states probed in this work span the temperature range of 673 to 1073 K and the density range of 0.17 to 0.34 g/cm3. The cluster size distributions and size of critical nuclei are reported. The size distribution of strontium chloride clusters shows a very strong dependence on the system density, with larger clusters forming faster at lower densities. The clusters composed of 15−30 ions appear critical over the temperature and density ranges examined. The nucleation rate values obtained in this work are on the order of 3 × 1028 to 9 × 1028 cm−3 s−1. Water is found in a substantial amount on the surface of larger SrCl2 clusters, with some water molecules being trapped for nanoseconds inside cages formed by surrounding ions in the interior of clusters.