Wednesday, October 05, 2011

Daniel Shechtman wins Chemistry Nobel for quasicrystals

Within the AP story on Daniel Shechtman winning the Nobel Prize for chemistry in 2011:

"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. (...)
Double Nobel winner Linus Pauling was among those who never accepted the findings.
"He would stand on those platforms and declare, 'Danny Shechtman is talking nonsense. There is no such thing as quasicrystals, only quasi-scientists.'" Shechtman said.

The beginning text of the Nobel discussion mentions what Daniel wrote in his lab notebook:

When Daniel Shechtman entered the discovery awarded with the Nobel Prize in Chemistry 2011 into his notebook, he jotted down three question marks next to it. The atoms in the crystal in front of him yielded a forbidden symmetry. It was just as impossible as a football – a sphere – made of only six- cornered polygons. Since then, mosaics with intriguing patterns and the golden ratio in mathematics and art have helped scientists to explain Shechtman’s bewildering observation.


Daniel Shechtman peeked out from his office into the corridor at the U.S. National Institute of Standards and Technology (NIST), wanting to find someone with whom he could share his discovery. But the corridor was empty, so he went back to the microscope to carry out further experiments on the peculiar crystal. Among other things, he double-checked if he had obtained a twin crystal: two intergrown crystals whose shared boundary gives rise to strange diffraction patterns. But he could not detect any signs that he was in fact looking at a twin crystal.
In addition to this, he rotated the crystal in the electron microscope in order to see how far he could turn it before the tenfold diffraction pattern reappeared. That experiment showed that the crystal itself did not have tenfold symmetry like the diffraction pattern, but was instead based on an equally impossible fivefold sym- metry. Daniel Shechtman concluded that the scientific community must be mistaken in its assumptions.
When Shechtman told scientists about his discovery, he was faced with complete opposition, and some col- leagues even resorted to ridicule. Many claimed that what he had observed was in fact a twin crystal. The head of the laboratory gave him a textbook of crystallography and suggested he should read it. Shechtman, of course, already knew what it said but trusted his experiments more than the textbook. All the commo- tion finally led his boss to ask him to leave the research group, as Schechtman himself recalled later. The situation had become too embarrassing.
Fighting established knowledge
Daniel Shechtman had obtained his Ph.D. from Technion – Israel Institute of Technology, and in 1983, he managed to get Ilan Blech, a colleague at his alma mater, interested in his peculiar research findings. Together they attempted to interpret the diffraction pattern and translate it to the atomic pattern of a crystal. They submitted an article to the Journal of Applied Physics in the summer of 1984. But the article came back seemingly by return of post – the editor had refused it immediately.
Shechtman then asked John Cahn, a renowned physicist who had lured him over to NIST in the first place, to take a look at his data. The otherwise busy researcher eventually did, and in turn, Cahn consulted with a French crystallographer, Denis Gratias, in order to see if Shechtman could have missed something. But according to Gratias, Shechtman’s experiments were reliable. Gratias would have proceeded in the same manner had he conducted the experiments himself.
In November 1984, together with Cahn, Blech and Gratias, Shechtman finally got to publish his data in Physical Review Letters. The article went off like a bomb among crystallographers. It questioned the most fundamental truth of their science: that all crystals consist of repeating, periodic patterns.

**See post from NIST

NIST Colleagues Congratulate Shechtman on Nobel Chemistry Prize :

Shechtman was on a two-year sabbatical and worked as a guest researcher at NIST from 1981 to 1983. He then returned to Technion, where he continued to pore over the diffraction pattern data that he had collected at NIST. In 1984, he returned to NIST at the invitation of Cahn, to consult further. Initial efforts to publish an article reporting five-fold symmetry were unsuccessful until November 12, 1984, when the landmark article was published in Physical Review Letters.


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