Hydrogen| Hydrogen |
In General > s.a. early-universe nucleosynthesis [deuterium];
molecular physics.
* Idea: The simplest, and the most abundant
element in the universe, by far; Hydrogen makes up 75 percent of all the visible mass in
the universe, and more than 90 percent of all the atoms.
* Properties: It easily forms compounds
with nearly all non-metallic elements on the periodic table, and its bonds with oxygen
and carbon are the reason why we exist; Hydrogen auto-ignites at 500 ºC.
@ General references: PW(95)jul issue; Rigden 02.
@ In quantum mechanics: Ogilvie a1603;
> s.a. composite quantum systems.
@ Related topics: Blanford et al PRL(98)
+ pn(98)apr [anti-H];
Korsheninnikov et al PRL(01)
+ pn(01)aug [5H],
PRL(03)
[7H, considered inconclusive];
news pw(05)aug [hydrino state];
news pn(07)jul [7H];
news PhysOrg(11)oct
[producing 99% pure H in a single device, without a separate purification step];
Stodolna et al PRL(13)
+ Smeenk Phy(13) [direct observation of excited states];
news(17)may hydrogen bonds detected].
Phases > s.a. high-temperature superconductors.
* Metallic form:
At high temperatures compressed hydrogen becomes a metallic liquid; 1935, Existence of this state
proposed by Wigner (at pressure of 250,000 bar); Initial attempts made with crystalline structure;
1968, Ashcroft proposal that solid metallic H could be a high-temperature superconductor;
1996, Obtained in disordered state, at pressures > 1.4 Mbar
[@ LLNL 1996
page; Weir et al PRL(96)
+ pn(96)mar];
2011, Solid hydrogen can exist in several different phases, phase IV obtained at 2.2 Mbar, arranged
into graphene-like sheets; 2016, Most of the planetary mass of the solar system may be in the form
of metallic hydrogen, mainly in the interiors of the giant planets; Several labs are still trying
to obtain solid metallic hydrogen, at 3–4 Mbar.
@ High-pressure behavior:
Strobel et al PRL(09)
+ Ashcroft Phy(09);
news sn(12)mar [new high-pressure phase, honeycombed atoms layered with free-floating molecules];
news PhysOrg(12)apr;
McMahon et al RMP(12)
[properties under extreme conditions];
news sa(16)jun
[metallic H inside planets];
news sn(16)aug [the search for solid metallic H];
news sn(17)jan,
csm(17)jan [debate on metallic form];
Celliers & Eggert Phy(17) [surprises].
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send feedback and suggestions to bombelli at olemiss.edu – modified 21 sep 2017