PROPERTIES OF SUPERCRITICAL WATER - AN AB-INITIO SIMULATION

Using ab initio molecular dynamics we have simulated the properties of supercritical water at the density rho=0.64 g/cm3 and temperature T=7 30 K. We calculate the neutron diffraction structure factors for vario us isotopic concentrations and find excellent agreement with experimen t. The real-space pair correlations are qualitatively similar and our calculations confirm that the conditions prevalent in supercritical wa ter disrupt the hydrogen bond network which characterizes water at amb ient temperatures and pressure. In a quantitative respect there are si gnificant differences between the simulation results for the pair corr elation functions and those obtained from the inversion of the experim ental data. We also studied some electronic properties of the system s uch as the average molecular dipole moment.