by Kathleen M. Wong

1926 was a very good year for science. Physicists Werner Heisenberg, Paul Dirac, and Erwin Schrödinger independently came up with mathematical ways to predict the locations of the electrons whirling about an atom’s nucleus.

The discovery was a critical one for chemists. The positions of electrons, and the ways they can be shared with other atoms, determine how atoms link into molecules and how molecules react with other molecules to form new substances. Describing these interactions is particularly important for organic chemists, who study the behavior of molecules containing carbon. Organic molecules can link into astonishingly intricate structures that can include multiple rings, side chains, lattices, and polymers. In nature, organic molecules form the basis of hormones and steroids, pheromones and poisons. In industry, they are synthesized into medicines and plastics, flavorings, pesticides, and much more.

Despite the help provided by quantum mechanics, many fine-grained details about organic chemistry still remain a black box. In 1929, Dirac wrote that with the discovery of quantum mechanics, "the underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble."

But solving such cumbersome equations is finally within reach. The computational obstacles presented by quantum mechanics equations, says professor of chemistry Kendall Houk of the University of California at Los Angeles, are tailor made for the number-crunching talents of supercomputers. For nearly two decades, he has depended on NCSA’s supercomputing resources to analyze the intricacies of organic reactions.

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Access Online | Posted 3-23-2004