Structural analysis of water at high temperatures and high pressures with rapid liquid X-ray diffractometer using imaging plate area detector

A novel X-ray diffraction method for liquids using an imaging plate area detector has been successfully applied to constant-density measurements of water at high temperatures and high pressures covering the supercritical state. The radial distribution functions have shown that the local tetrahedral ice-like structure of water is ruptured above 416K and that the short-range O-O interactions at ∼2.9A still exist by ∼40% to the coordination number of 3.9, however, with large fluctuation and distorted hydrogen bonding in dense supercritical water at 649K. (author)