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The phase diagram of H 2 O exhibits a substantial array of stable and meta-stable crystalline phases, along with two amorphous ices ().Terrestrial experiment continues to find new phases ().There are also good cosmochemical reasons to think about the high pressure phases of H 2 O—ice is a major component of the outer planets in our solar …
We have extensively explored the high-pressure structures of lithium (Li), potassium (K), and rubidium (Rb) using an ab initio evolutionary algorithm. For Li, an unexpected cubic P 4 1 32 structure containing sixfold coordinated lithium atoms and Li 3 equilateral triangles was discovered to be stable above 300 GPa. This structure is …
The new structure was found to be more stable than Cmca-12, a structure that was previously found to be a valid candidate in the H 2 -PRE phase, one of the six …
Here, using the same approach, we investigate the high-pressure structures of MgCO 3. Two new structure types were predicted to be stable in the relevant pressure range: one at 82–138 GPa and the other above 138 GPa. Both phases contain rings of corner-sharing CO 4-tetrahedra. These predictions were largely confirmed by the …
Here, we report the structure of the elusive high-pressure high-temperature polymorph ι–N 2 at 56 GPa and ambient temperature, determined by single crystal X-ray diffraction, and investigate ...
The high-pressure behavior of silicon carbide (SiC), a hard, semi-conducting material commonly known for its many polytypic structures and refractory nature, has increasingly become the subject of current research. Through work done both experimentally and computationally, many interesting aspects of high-pressure SiC have …
The structures of gypsum at pressures up to approximately 4 GPa are studied with density functional theory (DFT) and thoroughly compared with single-crystal X-ray diffraction experiments reported in the literature [Comodi et al. in (Am Miner 93:1530–1537, 2008)]. It is found that the exchange–correlation density functional revPBE …
Sustained progress in high-pressure experimental techniques has led to the discovery of numerous new high-pressure materials, and developments in …
We predicted three new high-pressure structures of RbN 3 with P-1, P6/mmm and C2/m structure at pressure of 30, 50 and 200 GPa. This result extends the high-pressure structures RbN 3 .
High-pressure behavior of SiO 2 is one of the prototypical subjects in several research areas including condensed matter physics, inorganic chemistry, mineralogy, materials science, and crystallography. Therefore, numerous studies have been performed on the structure evolution of SiO 2 under pressure. Here, we show a new …
The adoption of an open structure at high pressure suggested the presence of directional bonds. Therefore, a localized atomic hybrid orbital description of the chemical bonding …
Carbon is an element with extremely versatile bonding properties and theoretical calculations have suggested the possible existence of several hundred structural allotropes. Many, or even most, of these are predicted to be formed under conditions of high pressure and temperature. On the other hand, experimental high pressure studies have ...
The experimental discovery of the highest, up to 0 degree Celsius, superconducting transition temperatures T $$_c$$ c in the class of so-called hydrides under high pressure is undoubtedly the striking event in modern physics. In this paper, we give a short overview of the some history of the room-temperature conventional …
Abstract. Lithium is found to transform from a body-centered cubic (bcc) to a face-centered cubic (fcc) structure at 6.9 gigapascals (69 kilobars) and 296 kelvin. The relative volume of the bcc structured lithium at 6.9 gigapascals is 0.718, and the fcc structure is 0.25 percent denser. The bulk modulus and its pressure derivative for the bcc ...
The rutile structure has higher enthalpy than both the phase II structure and the P4 1 2 1 2 structure over this pressure range. At much higher pressures, >≈300 GPa, the enthalpy of the layered phase is lower than that of 3-dimensional extended phases. The polymeric phases all have similar low compressibilities but the rutile structure is ...
The high-pressure phase (Phase II) of Pt 2 HgSe 3 possesses a monoclinic structure with space group Pc. The details of crystallographic data are shown in Table 1 . The predicted crystal structure ...
Synthesis and crystal structure of FeN. The phase with the chemical composition FeN and the B8 (NiAs) structure type (Fig. 1b) was observed at each pressure-temperature point (Table 1).Very ...
open access • In-situ high pressure measurement techniques enabled by diamond anvil cell are introduced. • Pressure modulated structural, optical, and electrical …
The high-pressure structures of NaCl have been extensively explored through a particle swarm structural search at zero temperature and pressure range of 0–800 GPa. In addition to the known low-pressure insulating phases, we find three novel orthorhombic high-pressure structures: oC8 (stable at 322–645 GPa), oI8 (stable at …
2.2 General rule of phase transitions under high pressure. Since the pioneering study by Dyadin et al. (), many high-pressure studies have been published.A general rule of phase transitions in clathrate hydrates can be deduced from Fig. 1 (Hirai et al. 2004, 2008a, 2014; Loveday and Nelmes 2008; Hirai 2009).In general, the initial …
Structure and pair distribution functions. We examined three Zr-based metallic glasses: Zr 50 Cu 50-x Al 10 Pd x (x = 6, 15) and Zr 65 Cu 17 Ni 8 Al 10 quenched under pressure from a high ...
Superconductivity in the metallic elements at high pressures. 1. Introduction. The importance of high pressure studies to our understanding of condensed matter was …
Proteins denatured under high pressure have smaller partial molar volume than the native folded structure. This has been experimentally confirmed for many globular proteins, although the decrease in partial molar volume is rather small: typically the decrease is about 1–3% of the protein volume.27
Crystal structure searching and phase transition under pressure. Firstly, on the basis of the chemical constitution, we have conducted the structure prediction simulations of VH 2 in the pressure ...
It was synthesized at high temperature and high pressure of 5.5 GPa and systematically studied via structural, magnetic, and transport measurements at both …
Abstract. Lithium is found to transform from a body-centered cubic (bcc) to a face-centered cubic (fcc) structure at 6.9 gigapascals (69 kilobars) and 296 kelvin. The relative volume …
High-pressure X-ray diffraction combined with crystal structure prediction indicated that the structure changed from the P6 3 /mmc structure at ambient pressure into a new orthorhombic structure ...
It is found that TaH 6 with an estimated T c of 124.2–135.8 K under pressure is a candidate as a high-temperature superconductor . As for vanadium hydrides, the high-pressure structures of VH 5 and VH 8 have been explored, their T c values were predicted to be 18.5 and 71.4 K at 200 GPa due to the strong electron-phonon coupling (EPC ...
Here using ab initio crystal structure searching techniques, we explore the high-pressure phase transitions of ReS 2 extensively and predict two new high-pressure phases. The ambient pressure ...
We have investigated the pressure-induced phase transition and superconducting properties of niobium disulfide (NbS 2) based on the density functional theory.The structures of NbS 2 at pressures from 0 to 200 GPa were predicted using the multi-algorithm collaborative (MAC) structure prediction technique. The previously …
Here, we address this fundamental but open question of how hydrogen affects and reconstructs the yttium ionicity and local crystal structure under high pressure through a study of stoichiometric ...
