In the 1980s scientists invented cluster beam machines, that could generate and analyse particles with a precise number of atoms in the free beam (gas phase). They discovered “magic numbers”, certain sizes of clusters that were especially stable. The most famous discovery is the C₆₀ cluster, Buckminster fullerene, named after the geodesic dome built for the Montreal expo; C₆₀ led on to carbon nanotubes and then graphene. The approach of the Nanomaterials Lab, which has five cluster beam sources of various kinds, is to deposit a beam of nanoparticles onto a surface for analysis and for the assembly of functional systems. Passing the cluster beam through a mass-spectrometer enables a specific size to be selected. The size may control properties from magnetism to chemical reactivity. At the moment the Lab’s principal focus in this area is to tune the selectivity of a chemical reaction by controlling the arrangement of atoms and the electronic structure of supported nanoparticle catalysts.

Richard and Yubiao with the SUNS