Nature of the first-order phase transition in fluid phosphorus at high temperature and pressure.
An in situ x-ray diffraction experiment has been performed on phosphorus to characterize the liquid-liquid transition which occurs at high temperature and pressure. The transition line has been measured over an extended temperature range up to 2200 degrees C at 0.3 GPa. From the shape of this line, a thermodynamic characterization of the transition is obtained in terms of latent heat and internal energy change. Moreover, the addition of the high-pressure high-temperature data to the known phase diagram of phosphorus allows us to conclude that this is a first-order transition between a dense molecular fluid and a polymeric liquid.
Monaco
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European Synchrotron Radiation Facility, Boîte Postale 220, F-38042 Grenoble Cedex 9, France.
Falconi
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Crichton
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Mezouar
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