Posts Tagged ‘neon’
New Diamond Aerogel is the Airiest Diamond Ever Made
The result is a diamond aerogel, definitely the least dense diamond ever and perhaps one of the most valuable aerogels ever. Both aerogels and diamonds have interesting qualities, so a substance that combines their properties could be useful for, say, optics, quantum computing or structural engineering, among other possibilities.
Aerogels are porous, diffuse rigid materials, resembling a solid block of smoke in appearance and a chunk of Styrofoam in texture. They are used to insulate space suits, pick up cosmic particles, and even as . They’re made by constructing a conventional gel and then removing the liquid though supercritical drying. The resulting material is only slightly more dense than air — aerogels themselves are 90 percent air — but retains the structure and rigidity of the non-liquid gel components.
To make a diamond aerogel, Peter J. Pauzauskie and colleagues at Lawrence Livermore National Laboratory started with an amorphous carbon aerogel precursor and placed it in a diamond anvil cell, which is used to subject items to prodigious pressures. The team injected neon to prevent the aerogel from collapsing under the pressure, and subjected the substance to 21, 22.5 and 25.5 gigapascals — that’s about 200 to 250 times the pressure at the bottom of the Mariana Trench, in case you’re wondering. (It takes about 18 GPa to make a synthetic diamond.)
The resulting aerogel, confirmed through electron and X-ray spectromicroscopy, had a diffuse yet solid nanodiamond matrix. It’s transparent and pliable like plastic, and it even sparkles like the big ones, the researchers said. The aerogel possessed a bright and stable photoluminescence, which its precursor material did not. Diamonds emit electrons, so this particle emission could be useful for ultra-strong quantum information processors, the authors say.
The research appears in the Proceedings of the National Academy of Sciences.
[via ]
New Diamond Aerogel is the Airiest Diamond Ever Made
The result is a diamond aerogel, definitely the least dense diamond ever and perhaps one of the most valuable aerogels ever. Both aerogels and diamonds have interesting qualities, so a substance that combines their properties could be useful for, say, optics, quantum computing or structural engineering, among other possibilities.
Aerogels are porous, diffuse rigid materials, resembling a solid block of smoke in appearance and a chunk of Styrofoam in texture. They are used to insulate space suits, pick up cosmic particles, and even as . They’re made by constructing a conventional gel and then removing the liquid though supercritical drying. The resulting material is only slightly more dense than air — aerogels themselves are 90 percent air — but retains the structure and rigidity of the non-liquid gel components.
To make a diamond aerogel, Peter J. Pauzauskie and colleagues at Lawrence Livermore National Laboratory started with an amorphous carbon aerogel precursor and placed it in a diamond anvil cell, which is used to subject items to prodigious pressures. The team injected neon to prevent the aerogel from collapsing under the pressure, and subjected the substance to 21, 22.5 and 25.5 gigapascals — that’s about 200 to 250 times the pressure at the bottom of the Mariana Trench, in case you’re wondering. (It takes about 18 GPa to make a synthetic diamond.)
The resulting aerogel, confirmed through electron and X-ray spectromicroscopy, had a diffuse yet solid nanodiamond matrix. It’s transparent and pliable like plastic, and it even sparkles like the big ones, the researchers said. The aerogel possessed a bright and stable photoluminescence, which its precursor material did not. Diamonds emit electrons, so this particle emission could be useful for ultra-strong quantum information processors, the authors say.
The research appears in the Proceedings of the National Academy of Sciences.
[via ]
German Scientists Measure How Fast an Electron Jumps, the Shortest Time Interval Ever Measured
During photoemission – the expulsion of electrons from an atom by bombarding them with high-energy light – it’s always been assumed that there is no delay between the photons’ impact and the breaking loose of the target electron. But a group of German researchers in collaboration with Greek, Austrian, and Saudi Arabian colleagues decided to challenge that assumption with extremely sensitive time measurement tech.
The team bombarded atoms of neon gas with near-infrared laser light in 10-15 second pulses and ultraviolet pulses of far shorter durations of just 180 attoseconds (remember, an attosecond is one billionth of one billionth of one second). The near-IR light served as an attosecond chronograph, measuring the time of UV impact and the time the electrons exited their orbits.
Their findings turned up two interesting results. For one, they found that electron ejection is not a “time zero” action as once presumed, but that excited electrons hesitate very, very briefly before leaving the atom. But perhaps more interesting, they found that electrons from different orbitals behaved differently, leaving the atom at slightly different times even though they were impacted simultaneously.
The researchers are not exactly sure why this is, but it likely has to do with some small, overlooked influence that electrons exert over one another that is different that the forces exerted on electrons by their nuclei. If that’s the case, the tiny time lag could have big consequences for physics, a discipline ruled by the interactions between atoms and the behavior of electrons. Until they figure all that out, they can at least take pride in their 20-attosecond record for the shortest time interval ever directly measured.
[]