High pressure partially ionic phase of water ice.

摘要: Water ice dissociates into a superionic solid at high temperature (>2,000 K) and pressure, where oxygen forms the lattice, but hydrogen diffuses completely. At low temperature, however, dissociation an ionic of hydronium (H3O)+ hydroxide (OH)− is not expected because extremely energy cost (∼1.5 eV) proton transfer between H2O molecules. Here we show pressure-induced formation partially phase (monoclinic P21 structure) consisting coupled alternate layers (OH)δ− (H3O)δ+ (δ=0.62) in water predicted by particle-swarm optimization structural search zero pressures >14 Mbar. The occurrence this follows break-up typical O–H covalently bonded tetrahedrons symmetric atomic phases originated from volume reduction favourable for denser structure packing. Dissociation rare due to transfer. In study, simulation used predict which consists hydronium.