High-pressure calorimetric study on the ice XI–I h transition
1987; American Institute of Physics; Volume: 86; Issue: 9 Linguagem: Inglês
10.1063/1.452633
ISSN1520-9032
AutoresOsamu Yamamuro, Masaharu Oguni, Takasuke Matsuo, Hiroshi Suga,
Tópico(s)High-pressure geophysics and materials
ResumoA newly developed high-pressure calorimeter was used to measure the XI–Ih phase transition of ice doped with KOH (mole fraction 1.3×10−3) at two pressures: 0 and 158.9 MPa. The transition temperature was found to be (71.6±0.1) and (74.0±0.1) K at the respective pressures, resulting in its mean pressure dependence of (0.015±0.001) K MPa−1. With this dependence and the theoretical entropy of the transition for the complete transformation of the XI phase, 3.4 J K−1 mol−1, the application of the Clausius–Clapeyron’s equation yields (0.051±0.003) cm3 mol−1 for the volume change associated with the transition. From these results in conjunction with other data, negative volume expansivity, as observed in the proton disordered phase Ih at low temperatures, was also suggested for the proton ordered phase XI.
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