The mechanisms for pressure-induced amorphization of ice Ih

Article Abstract:

Quasi-harmonic lattice-dynamics were used to calculate the thermodynamic and mechanical stability boundaries of ice Ih under pressure. The results suggest that the pressure-induced phase transformation of ice Ih at low temperatures is not a thermodynamically melting transition, and high density amorphous (HDA) is therefore unlikely to have a liquid-like structure. Distinct differences between LDA ice and quenched liquid water were observed.

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Stable methane hydrate above 2 GPa and the source of Titan's atmospheric methane

Article Abstract:

Research is presented describing methane hydrate as the dominant methane-containing phase in the formation models of Saturn's largest moon, Titan. The research shows that the methane in Titan's primordial core remained in stable hydrate phases throughout differentiation, and eventually formed a 100-km thick layer of methane clathrate within the planet's ice mantle, which is possibly the replenishment source for Titan's atmospheric methane.

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Metastable ice VII at low temperature and ambient pressure

Article Abstract:

Pure ice VII may be obtained by cooling ice VI and compressing it below 95 K. It has been established that this phase can remain stable at atmospheric pressure and remains metastable indefinitely at 77 K. Recovered ice VII transforms into low-density amorphous ice. The availability of ice VII in gram quantities at ambient pressure presents new possibilities for its detailed characterization and comparison with ice VIII.

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