Surface molecular chain reaction initiated at STM-made individual active sites

The tip of a scanning tunneling microscope is used to manipulate individual atoms and to create, at predetermined sites on a germanium surface, single atom vacancies whose structure permits a selective reactivity towards molecular oxygen. These atomic vacancies appear to self-regenerate after reaction with oxygen, resulting in a remarkable oxygen induced chain reaction. Measured reaction parameters, such as chain breaking probabilities, are shown to provide access to detailed site dependent oxidation and diffusion rates of the atomic vacancies.