相关论文: Novel high-pressure calcium carbonates
We combine two first-principles computer simulation techniques, path integral Monte-Carlo and density functional theory molecular dynamics, to determine the equation of state of magnesium oxide in the regime of warm dense matter, with…
In an atmosphere, a cloud condensation region is characterized by a strong vertical gradient in the abundance of the related condensing species. On Earth, the ensuing gradient of mean molecular weight has relatively few dynamical…
The effects of pressure on the crystal structure of the three known polymorphs of magnesium sulfate have been theoretically study by means of DFT calculations up to 45 GPa. We determined that at ambient conditions gamma MgSO4 is an unstable…
Carbon monoxide (CO) is predicted to be the dominant carbon-bearing molecule in giant planet atmospheres, and, along with water, is important for discerning the oxygen and therefore carbon-to-oxygen ratio of these planets. The fundamental…
Using first-principles evolutionary simulations, we have systematically investigated phase stability in the Hf-O system at pressure up to 120 GPa. New compounds Hf5O2, Hf3O2, HfO and HfO3 are discovered to be thermodynamically stable at…
We investigate the elemental and isotopic stratification in the atmospheres of selected chemically peculiar (CP) stars of the upper main sequence. Reconfiguration of the UVES spectrograph in 2004 has made it possible to examine all three…
Atomistic simulations provide a meaningful way to determine the physico-chemical properties of liquids in a consistent theoretical framework. This approach takes on particular usefulness for the study of molten carbonates, in a context…
The compression of arsenolite (cubic As2O3) has been studied from a joint experimental and theoretical point of view. Experimental X-ray diffraction and Raman scattering measurements of this molecular solid at high pressures with different…
Carbonate precipitation in oceans is essential for the carbonate-silicate cycle (inorganic carbon cycle) to maintain temperate climates. By considering the thermodynamics of carbonate chemistry, we demonstrate that the ocean pH decreases by…
Most exoplanets with a few Earth radii are more inflated than bare-rock planets with the same mass, indicating a substantial volatile amount. Neither the origin of the volatiles nor the planet's bulk composition can be constrained from the…
Clouds are an integral part of planetary atmospheres, with most planets hosting clouds. The understanding of not only the formation, but also the composition of clouds is crucial to the understanding of future observations. As observations…
Recently (C.-T. Toh et al., Nature 577, 199 (2020)), the first synthesis of free-standing monolayer amorphous carbon (MAC) was achieved. MAC is a pure carbon structure composed of five, six, seven and eight atom rings randomly distributed.…
Theoretical models predict the condensation of silicon carbide around host stars with C/O ratios higher than 0.65 (cf. C/O$_{\mathrm{Sun}}$ = 0.54), in addition to its observations in meteorites, interstellar medium and protoplanetary…
Cycling of carbon dioxide between the atmosphere and interior of rocky planets can stabilize global climate and enable planetary surface temperatures above freezing over geologic time. However, variations in global carbon budget and…
Monte Carlo simulations, supplemented by ab initio calculations, shed light into the energetics and thermodynamic stability of nanostructured amorphous carbon. The interaction of the embedded nanocrystals with the host amorphous matrix is…
Gas hydrates are considered fundamental building blocks of giant icy planets like Neptune and similar exoplanets. The existence of these materials in the interiors of giant icy planets, which are subject to high pressures and temperatures,…
As the fourth most abundant element in the universe, carbon plays an important role in the physical and chemical evolution of the interstellar medium. Due to its unique property to form three different types of chemical bonds through sp^1,…
We unravel the distinct roles each cation plays in phase evolution, stability, and properties within Mg1/5Co1/5Ni1/5Cu1/5Zn1/5O high-entropy oxide (HEO) by integrating experimental findings, thermodynamic analyses, and first-principles…
Iron oxides play an increasingly prominent role in heterogeneous catalysis, hydrogen production, spintronics and drug delivery. The surface or material interface can be performance limiting in these applications, so it is vital to determine…
We demonstrate in this paper that high pressure can promote the reactions between the ionic compounds and H2 molecules and form thermodynamically stable hybrid compounds. Using crystal structure search method based on first principles…