Glasses that only a computer can make.

To create a glassy material from clusters would be to make the most disorderly solid possible -- one that could exhibit all sorts of unexpected properties, says R. Stephen Berry, a chemist at the University of Chicago.

Berry asked his computer to do just that by cooling 32-molecule clusters of potassium chloride as fast as necessary to turn them into glass. This simulation generated a billion structures, all possibly represented in the glassy material, he reported last week in Chicago at the Sixth International Symposium on Small Particles and Inorganic Clusters.

To achieve such variety, scientists would need to cool the molecules a trillion degrees Celsius per second -- 1,000 times faster than can now be done. "If you had the computer try to make it into a glass by cooling it at a rate possible in the lab, you'd never make a glass," Berry says.

But he doesn't mind. Berry simulated the salt clusters for two reasons: to try to develop efficient ways of analyzing data generated about clusters that size and to determine the forces that make the creation of glassy states so difficult. With this salt now simulated, he plans to model the conversion of magnesium, calcium, and barium oxides, and perhaps gallium arsenide, to glassy states.