Volume of supercooled water under pressure and the liquid-liquid critical point.
The volume of water (H(2)O) was obtained at about 200-275 K and 40-400 MPa by using emulsified water. The plot of volume against temperature showed slightly concave-downward curvature at pressures higher than ≈200 MPa. This is compatible with the liquid-liquid critical-point hypothesis, but hardly with the singularity-free scenario. When the critical point is assumed to exist at ≈50 MPa and ≈223 K, the experimental volume and the derived compressibility are qualitatively described by the modified Fuentevilla-Anisimov scaling equation.
Mishima
Osamu
O
Polyamorphism Group, Exploratory Nanomaterials Research Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan. mishima.osamu@nims.go.jp