High pressure-high temperature phase diagram of ammonia

Sandra Ninet (1) , Frédéric Datchi (1)

1 IMPMC - Institut de minéralogie et de physique des milieux condensés

The high pressure(P)-high temperature(T) phase diagram of solid ammonia has been investigated using diamond anvil cell and resistive heating techniques. The III-IV transition line has been determined up to 20 GPa and 500 K both on compression and decompression paths. No discontinuity is observed at the expected location for the III-IV-V triple point. The melting line has been determined by visual observations of the fluid-solid equilibrium up to 9 GPa and 900 K. The experimental data is well fitted by a Simon-Glatzel equation in the covered P-T range. These transition lines and their extrapolations are compared with reported calculations.

Mots clés: high pressure; ammonia; molecular solid; high temperature; melting curve

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Sandra Ninet, Frédéric Datchi. High pressure-high temperature phase diagram of ammonia. 2008. ⟨hal-00202017⟩