Related papers: Comment on High-Pressure Behavior of Hydrogen and …
Phase I of hydrogen has several peculiarities. Despite having a close-packed crystal structure, it is less dense than either the low temperature Phase II or the liquid phase. At high pressure, it transforms into either phase III or IV,…
The properties of hydrogen at high pressure have wide implications in astrophysics and high-pressure physics. Its phase change in the liquid is variously described as a metallization, H2-dissociation, density discontinuity or plasma phase…
Through a series of Raman spectroscopy studies, we investigate the behaviour of hydrogen-helium and hydrogen-nitrogen mixtures at high pressure across wide ranging concentrations. We find that there is no evidence of chemical association,…
Raman measurements performed on dense H2, D2 and H2+D2 in a wide pressure-temperature range reveal the presence of the {\Delta}J=0 rotational excitation. In the gas/fluid state this excitation has zero Raman shift, but in the solid, the…
The recent discovery of phase IV of solid hydrogen and deuterium consisting of two alternate layers of graphenelike three-molecule rings and unbound H2 molecules have generated great interests. However, vibrational nature of phase IV…
The interplay between electron correlation and nuclear quantum effects makes our understanding of elemental hydrogen a formidable challenge. Here, we present the phase diagram of hydrogen and deuterium at low temperatures and high-pressure…
Liquid atomic metallic hydrogen is the simplest, lightest, and most abundant of all liquid metals. The role of nucleon motions or ion dynamics has been somewhat ignored in relation to the dissociative insulator-metal transition. Almost all…
Recent dynamic compression experiments [M. D. Knudson et al., Science 348, 1455 (2015); P. M. Celliers et al., Science 361, 677 (2018)] have observed the insulator-metal transition in dense liquid deuterium, but with an approximately 95 GPa…
Quantum effects in condensed matter normally only occur at low temperatures. Here we show a large quantum effect in high-pressure liquid hydrogen at thousands of Kelvins. We show that the metallization transition in hydrogen is subject to a…
In their recent work Dias and Silvera (Science 2017) claim to have observed the Wigner-Huntington transition of hydrogen to a metallic state (MH) at a pressure of 495 GPa at low temperatures. The evidence for this transition is based on a…
Quantum nuclear zero-point motions in solid H$_2$ and D$_2$ under pressure are investigated at 80 K up to 160 GPa by first-principles path-integral molecular dynamics calculations. Molecular orientations are well-defined in phase II of…
Two new phases of hydrogen have been discovered at room temperature in Ref.1: phase IV above 220 GPa and phase V above ~270 GPa. In the present work we have found a new phase VI at P~360 GPa and T<200 K. This phase is likely metallic as…
In recent years there has been intense experimental activity to observe solid metallic hydrogen. Wigner and Huntington predicted that under extreme pressures insulating molecular hydrogen would dissociate and transition to atomic metallic…
In the quest to make metallic hydrogen at low temperatures a rich number of new phases have been found and the highest pressure ones have somewhat flat phase lines, around room temperature. We have studied hydrogen to static pressures of…
Dias and Silvera (Letters, p. 715, 2017) claim the observation of the Wigner-Huntington transition to metallic hydrogen at 495 GPa. We show that neither the claims of the record pressure or the phase transition to a metallic state are…
Results of X-ray diffraction experiments on solid oxygen at low temperature and at pressures up to 10 GPa are presented.A careful sample preparation and annealing around 240 K allowed to obtain very good diffraction patterns in the…
Loubeyre, Occelli, and Dumas (LOD) [1] claim to have produced metallic hydrogen (MH) at a pressure of 425 GPa, without the necessary supporting evidence of an insulator to metal transition. The paper is much ado about nothing. Most of the…
Experiments and computer simulations have shown that the melt-ing temperature of solid hydrogen drops with pressure above about 65 GPa, suggesting that a liquid state might exist at low temperatures. It has also been suggested that this low…
A new experimental study by Snider et al. [Nature 586, 373-377 (2020)] reported behavior in a high-pressure carbon-sulfur-hydrogen system that has been interpreted by the authors as superconductivity at room temperature. The sudden drop of…
Understanding high-pressure transitions in prototypical linear diatomic molecules, such as hydrogen, nitrogen, and oxygen, is an important objective in high-pressure physics. Recent ultrahigh-pressure study on hydrogen revealed that there…