UNL Researchers Come Up Golden

LINCOLN - Within a gold wedding band is a formation of atoms that no one knew was there until University of Nebraska-Lincoln scientists began taking a look.

  
University of Nebraska-Lincoln
chemist Xiao Cheng Zeng's
research on gold atoms led to
the discovery of clusters of the
atoms called buckyballs, a
model of which is shown here.  

Now, for the first time, this peculiar array of atoms - shaped like a cage and called a buckyball - is known to exist in a metal.

The discovery opens new possibilities for how gold, when reduced to its smallest form, can be used. Gold in its nano form could someday speed the production of hydrogen or form magnetic particles to help in medical treatment.

The new finding is so significant that it is the May cover story in the Proceedings of the National Academy of Sciences, one of the top three scientific journals in the world.

The buckyball cluster of atoms was first discovered in carbon more than 20 years ago and was named for the geodesic dome designed by Buckminster Fuller.

The scientists who made that discovery were awarded a Nobel Prize in chemistry in 1996. It essentially meant there were three natural forms of carbon - diamonds, graphite and buckyball.

Like the first time around, the gold buckyball discovery came as a surprise. UNL chemist Xiao Cheng Zeng and graduate student Satya Bulusu thought their research of gold atoms would find more "pancake-shaped" clusters as are known to exist in gold.

But they learned that when only 16 to 19 atoms of gold are present, they link together in a ball with a hollow center.

After seeing the result, the scientists were gleeful.

"We worked for 20 hours a day for the next few days to check what we were doing," Zeng said.

The actual ball created by 17 atoms, Zeng said, is about a few millionths of a hair wide. But the center is big enough to allow outside or "guest" atoms to be inserted that could change the way the material behaves.

"When gold is in bulk, it is very stable and won't rust. That is why we use it in currency and Olympic medals," Zeng said. "But when you cut it into billions of pieces, it no longer behaves like big gold."

Zeng, 43, created the buckyball image using PrairieFire, the university's supercomputer. The resulting theory was then turned over to physics researchers at Washington State University for final experimentation.

Zeng and Bulusu collaborated on the journal article with physicist Lai-Sheng Wang and graduate student Xi Li of Washington State.

Now that the finding is published, Zeng said, the news could trigger a gold rush of sorts in laboratories around the world.

"A lot of scientists will tackle it," he said. "It makes gold even more unique."

The gold buckyball discovery is the latest of many scientific breakthroughs for Zeng, who in 13 years has become one of UNL's most consistently published scientists.

This is his fourth finding to be published in the Proceedings of the National Academy of Sciences. University officials were uncertain whether it was the first time that a UNL scientist had made the cover of the journal.

Zeng, son of a physics professor at the University of Beijing in China, came to the United States to get his doctorate in chemistry at Ohio State University. "I'm a Buckeye," he said.

He was honored in 2004 with a Guggenheim Fellowship for his work in developing nanostructures of silicon.

"Zeng is one of our very top faculty," said Monica Norby, assistant vice chancellor for research. "We are very fortunate to have him here."

Reprinted from Omaha World-Herald