Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Buckyballs make room for gilded cages

17.05.2006


Carbon fullerenes now have metallic cousins, ‘hollow golden cages’


Au16, the world’s smallest hollow gold cage.



Scientists have uncovered a class of gold atom clusters that are the first known metallic hollow equivalents of the famous hollow carbon fullerenes known as buckyballs.
The evidence for what their discoverers call "hollow golden cages" appeared today in the online early edition of the Proceedings of the National Academy of Sciences.

The fullerene is made up of a sphere of 60 carbon (C) atoms; gold (Au) requires many fewer--16, 17 and 18 atoms, in triangular configurations more gem-like than soccer ball. At more than 6 angstroms across, or roughly a ten-millionth the size of this comma, they are nonetheless roomy enough to cage a smaller atom.



"This is the first time that a hollow cage made of metal has been experimentally proved," said Lai-Sheng Wang, the paper’s lead corresponding author.

Wang is an affiliate senior chief scientist at the Department of Energy’s Pacific Northwest National Laboratory and professor of physics at Washington State University. The experiments were buttressed and the clusters’ geometry deciphered from theoretical calculations led by Professor Xiao Cheng Zeng of the University of Nebraska and co-corresponding author.

Wang, who worked in the Richard Smalley lab that gave the world buckyballs, is part of a large cluster of researchers who have spent much of the past decade attempting to find the fullerene’s kin in metal. But their search has proved difficult because of metal clusters’ tendency to compact or flatten.

Experiments at the PNNL-based W.R. Wiley Environmental Molecular Sciences Laboratory elicited the photoelectron spectra of clusters smaller than Au32, which had been theorized as the gold-cage analog to C60 but ruled out by Wang’s group in an experiment that showed it as being a compact clump.

They instead turned their attention to clusters smaller than 20 atoms, which earlier work by Wang’s group showed were 3-D-- a golden pyramid, no less--but larger than 13 atoms, known to be flat. The spectra and calculations showed that clusters of 15 atoms or fewer remained flat but that all but one possible configuration of 16, 17 and 18 atoms open in the middle. At 19 atoms, the spaces fill in again to form a near-pyramid.

"Au-16 is beautiful and can be viewed as the smallest golden cage," Wang said. He pictures it as having "removed the four corner atoms from our Au20 pyramid and then letting the remaining atoms relax a little," and thus opening up space in its center.

It and its larger neighbors are stable at room temperature and are known as "free-standing" cages--unattached to a surface or any other body, in a vacuum. "When deposited on a surface, the cluster may interact with the surface and the structure may change."

Wang and his co-workers suspect "that many different kinds of atoms can be trapped inside" these hollow clusters, a process called "doping." "These doped cages may very well survive on surfaces," suggesting a method for influencing physical and chemical properties at smaller-than-nano scales, "depending on the dopants."

Wang’s group has not yet attempted to imprison a foreign atom in the hollow Au cages, but they plan to try.

Bill Cannon | EurekAlert!
Further information:
http://www.pnl.gov

More articles from Physics and Astronomy:

nachricht Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

nachricht Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>