ABSTRACT
The scanning tunneling microscope (STM) has the unique ability to image atoms and molecules at surfaces at unprecedented detail. It can also be employed to manipulate matter, at a very local scale. This overview discussed the use of STM to control and trigger chemical reactions. It can induce reactions between individual atoms and molecules, as well as in large assemblies and in full monolayers of molecules. This triggering can be accomplished by the application of local voltage pulses by the STM tip, which inject high energy charge carriers into chemical bonds, by applying specific bias voltage potentials between tip and surface or by electrochemical control of an entire surface. These manipulations enable the breaking or making of chemical bonds, the polymerization of molecules in well-defined structural geometries, or the controlled change of molecular redox states. The triggering of reactions can be carried out in extremely controlled environments (high vacuum, low temperature) or in mild environment such as solid/liquid interfaces at room temperature. The result of such manipulations of molecules and assemblies can be verified in a highly appealing way: by imaging them with STM at submolecular scale.
