Isaac Silvera Manages to Finally Smush Hydrogen to a Metal

by Tommy on 27/01/2017

Here are some cool numbers for you.

http://science.sciencemag.org/content/early/2017/01/25/science.aal1579

Observation of the Wigner-Huntington transition to metallic hydrogen, Ranga P. Dias and Isaac F. Silvera, Science (26 January 2017), doi:10.1126/science.aal1579

Producing metallic hydrogen has been a great challenge to condensed matter physics. Metallic hydrogen may be a room temperature superconductor and metastable when the pressure is released and could have an important impact on energy and rocketry. We have studied solid molecular hydrogen under pressure at low temperatures. At a pressure of 495 GPa hydrogen becomes metallic with reflectivity as high as 0.91. We fit the reflectance using a Drude free electron model to determine the plasma frequency of 32.5 ± 2.1 eV at T = 5.5 K, with a corresponding electron carrier density of 7.7 ± 1.1 × 1023 particles/cm3, consistent with theoretical estimates of the atomic density. The properties are those of an atomic metal. We have produced the Wigner-Huntington dissociative transition to atomic metallic hydrogen in the laboratory.

Wow, that’s three times the charge carrier density of bismuth iodide.

Update 1: Nobody believes this, apparently. Who knew!

Update 2: Eremets et al. checks in.

https://arxiv.org/abs/1702.05125

Comments on the claimed observation of the Wigner-Huntington Transition to Metallic Hydrogen, M.I. Eremets and A. P. Drozdov (16 February 2017)

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 high electron carrier density deduced from a Drude free electron model fitted to the reflectivity of the sample. Based on our analysis of the reflectivity data we find no convincing evidence for metallic hydrogen in their published data. The pressure determination is also ambiguous – it should be ~630 GPa according to the presented Raman spectrum. For comparison, we present our own data on the observation of highly reflecting hydrogen at pressures of 350-400 GPa. The appearance of metallic reflectivity is accompanied with a finite electrical conductivity of the sample. We argue that the actual pressure in the experiment of Dias and Silvera is likely below 400 GPa. In this case the observed enhanced reflectivity would be related to the phase transformation to conductive state published in arXiv:1601.04479.

So I can’t wait until they smush bismuth iodide again.

It won’t take this much effort.

I want a third opinion.

Update 3: Yet another published dissenting opinion.

https://arxiv.org/abs/1702.07192

Comment on: Observation of the Wigner-Huntington transition to metallic hydrogen, Paul Loubeyre, Florent Occelli and Paul Dumas (23 February 2017)

In a recently published article, Ranga P. Dias & Isaac F. Silvera have reported the visual evidence of metallic hydrogen concomitantly with its characterization at a pressure of 495 GPa and low temperatures. We have expressed serious doubts of such a conclusion when interviewed to comment on this publication. In the following comment, we would like to detail the reasons, based on experimental evidences obtained by us and by other groups worldwide that sustain our skepticism. We have identified two main flaws in this paper, as discussed in details below: the pressure is largely overestimated; the origin of the sample reflectivity and the analysis of the reflectance can be seriously questioned.

This will all be forgotten when they start smushing bismuth iodide, with extra hydrogen.

Update 4: Apparently the metallic hydrogen evaporated and escaped the vwessel. Vwessel.

If you have seen this vapor, please return it to its rightful owner. Thanks.

Update 5: And finally, this devastating comeback.

https://arxiv.org/abs/1704.07601

Comment on “Observation of the Wigner-Huntington transition to metallic hydrogen”, Xiao-Di Liu, Philip Dalladay-Simpson, Ross T. Howie, Bing Li and Eugene Gregoryanz (25 April 2017)

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 supported by any data and contradict the authors’ own unconfirmed previous results.

You know the saying, if at first you don’t succeed …

I’m sure they will get this all sorted out.

lifeform@charter.net

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