Editing Metallic hydrogen (section)

===Other experimental research, 1996–2004===
Many experiments are continuing in the production of metallic hydrogen in laboratory conditions at static compression and low temperature. Arthur Ruoff and Chandrabhas Narayana from [[Cornell University]] in 1998,<ref>{{cite journal |last1=Ruoff |first1=A. L. |display-authors=etal |year=1998 |title=Solid hydrogen at 342&nbsp;GPa: No evidence for an alkali metal |journal=[[Nature (journal)|Nature]] |volume=393 |issue=6680 |pages=46–49 |bibcode=1998Natur.393...46N |doi=10.1038/29949|s2cid=4416578 }}</ref> and later Paul Loubeyre and René LeToullec from [[Commissariat à l'Énergie Atomique]], [[France]] in 2002, have shown that at pressures close to those at the [[planetary core|center of the Earth]] ({{convert|3200000|-|3400000|atm|GPa|order=flip|disp=or|abbr=on}}) and temperatures of {{convert|100|-|300|K|C|abbr=on}}, hydrogen is still not a true alkali metal, because of the non-zero band gap. The quest to see metallic hydrogen in laboratory at low temperature and static compression continues. Studies are also ongoing on [[deuterium]].<ref>{{cite journal |last1=Baer |first1=B.J. |last2=Evans |first2=W.J. |last3=Yoo |first3=C.-S. |year=2007 |title=Coherent anti-Stokes Raman spectroscopy of highly compressed solid deuterium at 300&nbsp;K: Evidence for a new phase and implications for the band gap |journal=[[Physical Review Letters]] |volume=98 |issue=23 |page=235503 |bibcode=2007PhRvL..98w5503B |doi=10.1103/PhysRevLett.98.235503|pmid=17677917 |url=https://zenodo.org/record/1233957 }}</ref> Shahriar Badiei and Leif Holmlid from the [[University of Gothenburg]] have shown in 2004 that condensed metallic states made of excited hydrogen atoms ([[Rydberg matter]]) are effective promoters to metallic hydrogen,<ref>{{cite journal |last1=Badiei |first1=S. |last2=Holmlid |first2=L. |year=2004 |title=Experimental observation of an atomic hydrogen material with H–H bond distance of 150&nbsp;pm suggesting metallic hydrogen |journal=[[Journal of Physics: Condensed Matter]] |volume=16 |issue=39 |pages=7017–7023 |bibcode=2004JPCM...16.7017B |doi=10.1088/0953-8984/16/39/034|s2cid=250885119 }}</ref> however these results are disputed.<ref>{{cite conference | title=Comment on 'Ultradense protium p(0) and deuterium D(0) and their relation to ordinary Rydberg matter: a review' 2019 Physica Scripta 94, 075005 | author=Klavs Hansen | year=2022| arxiv=2207.08133 }}</ref>