Sodium loses its luster: A liquid metal that's not really metallic
September 26, 2007
Unlike other solid metals, sodium melts differently when additional pressure is added. Image: Kwei-Yu Chu/LLNL
When melting sodium at high pressures, the material goes through a transition in which its electrical conductivity drops threefold. In a series of new calculations, Lawrence Livermore National Laboratory scientists describe the unusual melting behavior of dense sodium.
“We found that molten sodium undergoes a series of pressure-induced structural and electronic transitions similar to those observed in solid sodium but beginning at a much lower pressure,” said LLNL’s Eric Schwegler.
Schwegler and former colleagues Stanimir Bonev, now at Dalhousie University in Nova Scotia, and Jeans-Yves Raty at FNRS-University of Ličge in Belgium report the new findings in the Sept. 27 edition of the journal, Nature.
Earlier experimental measurements of sodium’s melting curve have shown an unprecedented pressure-induced drop in melting temperature from 1,000 K at 30 GPa (30,000 atmospheres of pressure) down to room temperature at 120 GPa (120 million atmospheres of pressure).
Usually when a solid melts, its volume increases. In addition, when pressure is increased, it becomes increasingly difficult to melt a material.
However, sodium tells a different story.
As pressure is increased, liquid sodium initially evolves into a more compact local structure. In addition, a transition takes place at about 65 GPa that is associated with a threefold drop in electrical conductivity.
The researchers carried out a series of first-principle molecular dynamic simulations between 5 and 120 GPa and up to 1,500 K to investigate the structural and electronic changes in compressed sodium that are responsible for the shape of its unusual melting curve.
The team discovered that in addition to a rearrangement of the sodium atoms in the liquid under pressure, the electrons were transformed as well. The electronic cloud gets modified; the electrons sometimes get trapped in interstitial voids of the liquid and the bonds between atoms adopt specific directions.
“This behavior is totally new in a liquid as we usually expect that metals get more compact with pressure,” Raty said.
Source: Lawrence Livermore National Laboratory
-
Getting salty: Can beet juice, other alternatives help to keep the nation's highways ice-free?
Dec 20, 2010 |
5 / 5 (3) |
0
-
The boundless promise -- and mystery -- of glass
Aug 02, 2010 |
5 / 5 (5) |
0
-
Researchers discover water on the moon is widespread, similar to Earth's
Jul 21, 2010 |
5 / 5 (23) |
25
-
Researchers study salt's potential to store energy
Jun 02, 2009 |
4.3 / 5 (7) |
1
-
'Cold' Mars Could Have Harbored Liquid Water
Jun 01, 2009 |
4.4 / 5 (10) |
7
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (31) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
-
excited U-236 decay time in the U235 fission chain
Feb 09, 2012
-
Polar catastrophe?
Feb 09, 2012
-
Large scale field sonication
Feb 09, 2012
-
states and energy of paired electrons in BCS
Feb 08, 2012
-
difference between longitudinal and transverse refractive indices
Feb 08, 2012
-
Monte Carlo simulation
Feb 07, 2012
- More from Physics Forums - Atomic, Solid State, Comp. Physics
More news stories
Putting the squeeze on planets outside our solar system
(PhysOrg.com) -- Using high-powered lasers, scientists at Lawrence Livermore National Laboratory and collaborators discovered that molten magnesium silicate undergoes a phase change in the liquid state, abruptly ...
10 hours ago |
4.3 / 5 (7) |
0
|
Hovering not hard if you're top-heavy, researchers find
Top-heavy structures are more likely to maintain their balance while hovering in the air than are those that bear a lower center of gravity, researchers at New York University's Courant Institute of Mathematical Sciences ...
11 hours ago |
5 / 5 (1) |
1
|
SLAC, Stanford team focuses on high-energy electrons to treat cancer
Accelerator physicists at SLAC and cancer specialists from Stanford are working on a new technology that could dramatically reduce the time needed for cancer radiation treatments. The team ran an initial experiment ...
14 hours ago |
5 / 5 (2) |
0
Measurements from high-energy collisions lead to better understanding of why meson particles disappear
For several years, physicists at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), USA, have studied an unusual state of matter called the quarkgluon plasma, which they ...
15 hours ago |
4.5 / 5 (4) |
0
Explained: Sigma
It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...
Feb 09, 2012 |
5 / 5 (16) |
53
Google users warned of threat to smartphone wallets
Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.
Anonymous knocks CIA website offline (Update)
The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.
New error-correcting codes guarantee the fastest possible rate of data transmission
Error-correcting codes are one of the triumphs of the digital age. Theyre a way of encoding information so that it can be transmitted across a communication channel such as an optical fiber o ...
Humans may have helped the decline of African rainforests 3000 years ago
(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...
Complex wiring of the nervous system may rely on a just a handful of genes and proteins
Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...
New power source discovered
(PhysOrg.com) -- Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation.