X-ray and neutron structural study on water under high pressure and high temperature, 2

Katayama, Yoshinori; Hattori, Takanori   ; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami   ; Suzuya, Kentaro; Chiba, Ayano*; Otomo, Toshiya*

Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water by in-situ synchrtorn X-ray diffraction experiments at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neturon diffraction measurements on heavy water at 100C and 200C at 2 GPa using high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of width of first peak in diffraction pattern, which is similar to that observed in the previous neutron diffraction experiments at 0.8 GPa.