相关论文: Superionic to superionic phase change in water: co…
Knowing the phase transformations in dense water ice is key to unraveling the peculiar geophysical properties of Uranus and Neptune, whose stratified interior models predict a thick ice layer beneath a convective ionic fluid layer. In the…
Uranus and Neptune are characterized by anomalously tilted and multi-dipole magnetic fields, which poses substantial challenges for elucidating the internal mechanisms generating magnetic fields. Recent investigations confirmed that…
Water is abundant in natural environments but the form it resides in planetary interiors remains uncertain. We report combined synchrotron X-ray diffraction and optical spectroscopy measurements of H2O in the laser-heated diamond anvil cell…
Most water in the universe may be superionic, and its thermodynamic and transport properties are crucial for planetary science but difficult to probe experimentally or theoretically. We use machine learning and free energy methods to…
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…
The ice giant planets Uranus and Neptune are assumed to contain large amounts of planetary ices such as water, methane, and ammonia. The properties of mixtures of such ices at the extreme pressures and temperatures of planetary interiors…
The impact of the inner structure and thermal history of planets on their observable features, such as luminosity or magnetic field, crucially depends on the poorly known heat and charge transport properties of their internal layers. The…
Superionic ice, where water molecules dissociate into a lattice of oxygen ions and a rapidly diffusing 'gas' of protons, represents an exotic state of matter with broad implications for planetary interiors and energy applications. Recently,…
Aptly named, ice giants such as Uranus and Neptune contain significant amounts of water. While this water cannot be present near the cloud tops, it must be abundant in the deep interior. We investigate the likelihood of a liquid water ocean…
Interior models of Uranus and Neptune often assume discrete layers, but sharp interfaces are expected only if major constituents are immiscible. Diffuse interfaces could arise if accretion favored a central concentration of the least…
Uranus and Neptune, the so-called "ice giants", represent a fascinating class of planets. They are the outermost planets in the solar system with intermediate masses/sizes, complex non-polar magnetic fields, strong atmospheric winds, and…
Weck et al. (1) report on the existence and stability fields of two superionic (SI) phases of H2O ice at high P-T (P-T) conditions, which has been a topic of static and dynamic experiments and theoretical calculations (see Ref. (2) and…
Polyhydrides have been shown to form novel structures at high pressure, which may be found in the interiors of giant planets. With density functional molecular dynamics simulations we studied the behavior of ammonium polyhydride compounds…
Using density functional molecular dynamics simulations, we study the behavior of different hydrogen-oxygen compounds at megabar pressures and several thousands of degrees Kelvin where water has been predicted to occur in superionic form.…
Ab initio free energy calculations are employed to derive the entropy of liquid and superionic water over a wide range of conditions in the interiors of Uranus and Neptune. The resulting adiabats are much shallower in pressure-temperature…
We present a new framework for constructing agnostic and yet physical models for planetary interiors and apply it to Uranus and Neptune. Unlike previous research that either impose rigid assumptions or rely on simplified empirical profiles,…
As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometer or so is expected to freeze to form an elastic crust of increasingly neutron-rich…
Using ab initio simulations we investigate whether water ice is stable in the cores of giant planets, or whether it dissolves into the layer of metallic hydrogen above. By Gibbs free energy calculations we find that for pressures between 10…
The structure and stability of iron near melting at multi-megabar pressures are of significant interest in high pressure physics and earth and planetary sciences. While the body-centered cubic (BCC) phase is generally recognized as unstable…
The hydrogen ions in the superionic ice can move freely, playing the role of electrons in metals. Its electromagnetic behavior is the key to explaining the anomalous magnetic fields of Uranus and Neptune. Based on the ab initio evolutionary…