相关论文: The complex kinetics of the ice VI to ice XV hydro…
The D2O ice VI to ice XV hydrogen ordering phase transition at ambient pressure is investigated in detail with neutron diffraction. The lattice constants are found to be sensitive indicators for hydrogen ordering. The a and b lattice…
In the last decade five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen…
A new phase of ice, named ice XV, has been identified and its structure determined by neutron diffraction. Ice XV is the hydrogen-ordered counterpart of ice VI and is thermodynamically stable at temperatures below ~130 K in the 0.8 to 1.5…
More than 20 crystalline and amorphous phases have been reported for ice so far. This extraordinary polymorphism of ice arises from the geometric flexibility of hydrogen bonds and hydrogen ordering, and makes ice a unique presence with its…
Doping the hydrogen-disordered phases of ice V, VI and XII with hydrochloric acid (HCl) has led to the discovery of their hydrogen-ordered counterparts ices XIII, XV and XIV. Yet, the mechanistic details of the hydrogen-ordering phase…
We use electron momentum density in ice as a tool to quantify order-disorder transitions by comparing Compton profiles differences of ice VI, VII, VIII and XII with respect to ice Ih. Quantitative agreement is found between theory and…
We report a detailed ab initio investigation on hydrogen bonding, geometry, electronic structure, and lattice dynamics of ice under a large high pressure range, including the ice X phase (55-380GPa), the previous theoretically proposed…
The recent discovery of a low-temperature endotherm upon heating hydrochloric-acid doped ice VI has sparked a vivid controversy. The two competing explanations aiming to explain its origin range from a new distinct crystalline phase of ice…
From high precision measurements of the complex dielectric constant of H2O ice, we identify the critical temperatures of the phase transition into and out of ice XI from ice Ih to occur at T_Ih-IX=58.9 K and T_IX-Ih=73.4 K. For D2O,…
The properties of some forms of water ice reserve still intriguing surprises. Besides the several stable or metastable phases of pure ice, solid mixtures of water with gases are precursors of other ices, since in some cases they may be…
Proton ordering in water ice is a paradigmatic order-disorder transition in a locally constrained system. The ice rules require exactly two hydrogens close to each oxygen, restricting the disorder to an exponentially large yet strongly…
Water exhibits rich polymorphism, where more than 20 crystalline phases have been experimentally reported. Five of them are metastable and form at low temperatures by either heating amorphous ice or degassing clathrate hydrates. However,…
We report a detailed ab initio investigation on the optical properties of ice under a wide high pressure range. The ice X phase (up to 380GPa), the theoretical proposed higher pressure phase ice XV (300GPa), as well as the ambient pressure…
We discuss the problem of proton motion in Hydrogen bond materials with special focus on ice. We show that phenomenological models proposed in the past for the study of ice can be recast in terms of microscopic models in close relationship…
Ice Ih, the common form of ice in the biosphere, contains proton disorder. Its proton-ordered counterpart, ice XI, is thermodynamically stable below 72 K. However, even below this temperature the formation of ice XI is kinetically hindered…
We propose three new phases of H2O under ultrahigh pressure. Our structural search was performed using an adaptive genetic algorithm which allows an extensive exploration of crystal structure. The new sequence of pressure-induced…
We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase[Lobban et al.,Nature, 391, 268, (1998)], labeled ice XII, at completely different…
We present new cooling sequences, color-magnitude diagrams, and color-color diagrams for cool white dwarfs with pure hydrogen atmospheres down to an effective temperature $\te=1500$ K. We include a more detailed treatment of the physics of…
We study the isotope effect on the temperature of the proton order/disorder phase transition between ice XI and ice Ih, using the quasiharmonic approximation combined with \textit{ab initio} density functional theory calculations. We show…
Most experimentally known high-pressure ice phases have a body-centred cubic (bcc) oxygen lattice. Our atomistic simulations show that, amongst these bcc ice phases, ices VII, VII' and X are the same thermodynamic phase under different…