Ammonia ice at very high pressure

In this presentation, we report an extended experimental investigation of the phase diagram of ammonia at high pressure and temperature. By combining Raman scattering and X-ray diffraction experiments, we demonstrate the presence of a new H-disordered crystalline form above $\sim$60 GPa and $\sim$700 K. Using \textit{ab initio} MD simulations, we show that this new disordered phase is a superionic conductor. We will also present new experimental results (infrared, Raman and X-ray) on NH$_{3}$ and ND$_{3}$ at ambient temperature up to 200 GPa and will discuss the existence of ionic ammonia ices.