Wednesday, October 5, 2011

Israeli wins chemistry Nobel for quasicrystals

Israeli scientist Dan Shechtman was awarded the Nobel Prize in chemistry on Wednesday for a discovery that faced skepticism and mockery, even prompting his expulsion from his research team, before it won widespread acceptance as a fundamental breakthrough.
While doing research in the U.S. in 1982, Shechtman discovered a new chemical structure — quasicrystals — that researchers previously thought was impossible.
He was studying a mix of aluminum and manganese in an electron microscope when he found the atoms were arranged in a pattern — similar to one in some traditional Islamic mosaics — that appeared contrary to the laws of nature.
He concluded that science was wrong — but it would take years for him and other researchers to prove that he was right.
Since then, quasicrystals have been produced in laboratories and a Swedish company found them in one of the most durable kinds of steel, which is now used in products such as razor blades and thin needles made specifically for eye surgery, the Royal Swedish Academy of Sciences said. Quasicrystals are also being studied for use in new materials that convert heat to electricity. They were first discovered in nature in Russia in 2009.
Despite the initial reluctance in the scientific community to accept his discovery, it "fundamentally altered how chemists conceive of solid matter," the academy said in its citation for the 10 million kronor ($1.5 million) award.
"The main lesson that I have learned over time is that a good scientist is a humble and listening scientist and not one that is sure 100 percent in what he read in the textbooks," Shechtman, 70, told a news conference Wednesday at the Technion-Israel Institute of Technology in Haifa, Israel.
Shechtman is a professor there and at Iowa State University in Ames, Iowa. He will receive the award along with the other Nobel Prize winners at a Dec. 10 ceremony in Stockholm.
Israel has won 10 Nobel prizes, a source of great pride in the country of just 7.8 million people. Shechtman was congratulated by Israeli President Shimon Peres, who shared the Nobel Peace Prize as Israel's foreign minister in 1994, and by Prime Minister Benjamin Netanyahu.
"Every citizen of Israel is happy today and every Jew in the world is proud," Netanyahu said.
In chemical terms, a crystal is traditionally defined as a regular and repeating arrangement of atoms within a material. As a results of these repeats, traditional crystals can have only certain shapes.
What Shechtman found was a material that seemed to have a forbidden shape. Eventually, scientists realized it was a new kind of matter, a quasicrystal, in which the atomic patterns show a more subtle kind of repetition that allows forbidden shapes.
"His battle eventually forced scientists to reconsider their conception of the very nature of matter," the academy said.
Nancy B. Jackson, president of the American Chemical Society called Shechtman's discovery "one of these great scientific discoveries that go against the rules." When Shechtman announced it, other experts hesitated.
"People didn't think that this kind of crystal existed," she said. "They thought it was against the rules of nature."
Only later did some scientists go back to some of their own inexplicable findings and realized they had seen quasicrystals but not realized what they had, Jackson said.
"Anytime you have a discovery that changes the conventional wisdom that's 200 years old, that's something that's really remarkable," said Princeton University physicist Paul J. Steinhardt, who coined the term "quasicrystals" and had been doing theoretical work on them before Shechtman reported finding the real thing.
Steinhardt recalled the day when a fellow scientist showed him Shechtman's paper in 1984, reporting the kind of result Steinhardt had predicted. "I sort of leapt in the air," he said.
Staffan Normark, permanent secretary of the Royal Swedish Academy, said Shechtman's discovery was one of the few Nobel Prize-winning achievements that can be dated to a single day.
On April 8, 1982, while on a sabbatical at the National Bureau of Standards in Washington, D.C. — now called the National Institute of Standards and Technology — Shechtman first observed crystals with a shape most scientists considered impossible.
It had to do with the idea that a crystal shape can be rotated by a certain amount and still look the same.
A square contains fourfold symmetry, for example: If you turn it by 90 degrees, a quarter-turn, it still looks the same. For crystals, only certain degrees of such symmetry were thought possible. Shechtman had found a crystal that could be rotated one-fifth of a full turn and still look the same, which was thought to be impossible.
"I told everyone who was ready to listen that I had material with pentagonal symmetry. People just laughed at me," Shechtman said in a description of his work released by his university.
For months he tried to persuade his colleagues of his find, but they refused to accept it. Finally he was asked to leave his research group, and moved to another one within the National Bureau of Standards, Shechtman said.
He returned to Israel, where he found one colleague prepared to work with him on an article describing the phenomenon. The article was at first rejected, but finally published in November 1984 — to uproar in the scientific world. Double Nobel winner Linus Pauling was among those who never accepted the findings.
"He really was a great scientist, but he was wrong. It's not the first time he was wrong," Shechtman told reporters Wednesday.More...

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