title: When is H2O not water?
abstract: We have combined a computational search strategy with first-principles density-functional-theory calculations to identify metastable phases of H(2)O under pressure. The most stable structures consist of water molecules, while the most energetic metastable phases consist of oxygen and hydrogen molecules. In between lie many other metastable phases, consisting of various combinations of a few small molecules. It may be possible to synthesize some of these metastable phases, and we use our results to understand the nature of the crystalline metastable phase of H(2)O recently synthesized by Mao et al. [Science 314, 636 (2006)].
authors.affiliation: Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom. cjp10@st-andrews.ac.uk
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pickard
authors.forename: R J
authors.initials: RJ
authors.lastname: Needs
mesh_terms: D000465:Algorithms; D003460:Crystallization; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D006859:Hydrogen; D010100:Oxygen