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Past Winner
2007 Gerhard Herzberg Canada Gold Medal for Science and Engineering

John C. Polanyi

Chemistry

University of Toronto


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For John Polanyi, the impulse to do science comes as naturally as breathing. "It's like asking, 'Why do you want to stay alive?' The reason is that you want to achieve something. It's an outgrowth of being alive that you are challenged to try to discover something."

That's an approach that has led to a number of major advances in chemistry over the years, notably helping pioneer the development of a new field known as reaction dynamics. Chemistry had traditionally concerned itself with the bulk properties of matter, focusing on what happened before and after a reaction. Reaction dynamics goes down to the molecular level in an effort to understand what happens during a reaction. That includes getting a clear picture of how things look during the brief instant (a millionth of a millionth of a second) when substances have begun to react but are not yet in their final state, as well as investigating the fundamental forces and motions that affect reactions at the molecular level.

Dr. Polanyi's choice of field was influenced in part by work on the molecular basis for chemical reactions done by his father, who was a Professor of Chemistry (and later a Professor of Philosophy) at Manchester University. In an effort to take this field of inquiry to the next level, he devoted his postdoctoral work at the National Research Council Canada to research that proved that the transition state theory, then the reigning theory of reaction rates, was based on an inadequate understanding of the forces at play during a reaction.

Those forces include the energy of the three types of motion experienced by molecules: rotation, vibration and the physical movement of the molecule from one point to another called translation. Dr. Polanyi's work helped illuminate how those three types of energy interact during a reaction, making it possible, thereafter, to exert more intelligent control over reactions.

After being appointed a professor at the University of Toronto in 1956, he began doing experiments based on the belief that he could detect a specific wavelength of infrared chemiluminescence – a minute emission of light – during the reaction of hydrogen and chlorine. That reaction releases substantial energy in the form of heat (which is molecular motion), but it was unknown how that energy was distributed among the three types of motion. His experiment helped unravel that mystery, providing a way to understand chemical reactions in more detail than had previously been possible. This discovery also paved the way for the creation of chemical and other vibrational lasers, which today remain the most powerful sources of infrared radiation. Subsequent work resulted in increasingly detailed observations of the transition state.

Among other accolades, his contributions to the field of reaction dynamics earned Dr. Polanyi a share of the 1986 Nobel Prize for Chemistry. Resting on his laurels is the furthest thing from his mind, however. "There are still a lot of things left to do in the world," he observes.

Still, new topics are not always easy to select; indeed the choice of the right question is vital. "It has to be a question worth asking, it has to have wide implications for a lot of different branches of science, and it has to be doable. It's very seldom that I find something that meets those requirements," he says.

One research area that has met his criteria involves exploring reactions that take place on the surface of a solid substance. It's a task made possible by the invention of the scanning tunneling microscope, which is able to image surfaces at the atomic level. Controlling the reaction process on an atomic scale, he has been able to arrange molecules in specific patterns and then bond them to the surface. The result marries reaction dynamics and surface science to make a "molecular printing press," patented technology that has potential applications in nanofabrication and electronics.

Dr. Polanyi is eager to find applications for his work, but emphasizes that he does not embark on new research with that as a goal. A staunch advocate for the importance of basic science, he argues that scientists should choose their research projects based on important gaps in knowledge, rather than real or imagined future applications. Basic science will lead inevitably to applications, although it may not be possible to predict how and when. "It would, in fact, be very hard to make an advance of any substance in science that would not have practical implications," he remarks.

"I'm fascinated by applications," he continues. "I think they help validate the importance of science. It's just that I don't want them to be the rudder that guides science."

Prior to winning the Nobel Prize, Dr. Polanyi's long list of honours included being named an Officer, and then a Companion, of the Order of Canada, and a Fellow of the Royal Societies of Canada, London and Edinburgh. He has received honorary degrees from universities around the world and won numerous scientific prizes.

His career has also included a long-time focus on political and social issues, particularly those related to science. Over the years he has written many articles on subjects such as arms control, peace and science policy. He was the co-founder and first Chair of the Canadian Pugwash Group, part of an international movement dedicated to understanding the social impact of science and preventing its misuse.

He feels it is incumbent on scientists to get involved in order to ensure that science is not misused. Discoveries themselves are not good or evil, only the purposes they are put to. "It's up to scientists, in the other half of their lives as citizens, to try to tilt the balance," he says. "What I try to do is get involved in the political process so that foolish or dangerous applications are not the ones that are pursued."

"I would hate not to be involved in public affairs. It's a privilege to be part of the political process."

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