Structure of Water at High Temperatures and Pressures.

Fluids at high pressures and temperatures

With high pressures, supercritical fluids can be studied over a very wide range of density. Fluids with strongly interacting polar molecules for example water are of particular interest. Results for several thermophysical properties are discussed. Density, dielectric constant and self—ionization of water have been determined or predicted to 1000 °C. Beyond 20 GPa very hot water appears to becom...

Near-Infrared Study of Water and Water-Benzene Mixtures at High Temperatures and Pressures

Near-infrared absorption of water and water-benzene mixtures has been measured at temperatures and pressures in the range of subcritical and supercritical condition of water. The molar absorption intensity of the OH stretching overtone transition of neat water was obtained. It decreases linearly with increasing pressure in the region of gas and gaslike density. Enthalpy for dimerization has bee...

Electrical conductivity of wadsleyite at high temperatures and high pressures

New phases of N2O4 at high pressures and high temperatures

High P–T studies of molecular N2O4 using Raman, synchrotron infrared, and X-ray diffraction measurements reveal several new phenomena. Significant changes in the vibrational spectra indicate a phase transition at about 12 GPa. The X-ray diffraction measurements show that the material remains cubic through the transition. We ascribe the transition to a change in the molecular geometry of N2O4 wi...

Spectroscopic study of mutual solubilities of water and benzene at high temperatures and pressures.

Near-infrared and ultraviolet absorption of water-benzene mixtures has been measured at temperatures and pressures in the ranges of 323-673 K and 50-400 bar, respectively. Concentrations of water and benzene in both the water-rich phase and the benzene-rich phase of the mixtures were obtained from absorption intensities of near-infrared bands of water and benzene and ultraviolet bands of benzen...