John Polanyi

This laboratory's long-time interest in the molecular motions responsible for chemical reactions at surfaces has received a major impetus in recent times with the advent of Scanning Tunneling Microscopy, the principle diagnostic tool used by the group. The laboratory is unusual in having four Ultra High Vacuum Scanning Tuneling Microscopes (STM) at its disposal. With the aid of these instruments it is able to characterize the event of chemical reactions a-molecule-at-a-time at a variety of semi-conductor and metallic surfaces.

A central finding is the localization of reaction close to the site at which the parent molecule (the reagent) physisorbs on the surface. This provides the basis for a method of maskless Molecular-Scale Imprinting, constituting a 'molecular printing press' in which the mobile molecular 'type' self-assembles, and subsequently permanently ‘imprints’ through localised chemical reaction with the underlying surface induced by heat, light or electrons. Novel mechanisms of self-assembly lead to such nano-structures as molecular corrals and switches. Studies of the imprinting step reveal detailed links between adsorbate geometry and reactivity. Experiment is supported in all cases by theory performed collaboratively with other research groups in Canada and the U.K.