Magic Nuclearity Giant Clusters of Metal Nanocrystals Formed by Mesoscale Self-Assembly

Magic, nuclearity giant clusters formed by the mesoscale self-assembly of Pd nanocrystals of 2.5 nm diameter (nuclearity, ∼561) have been identified by transmission electron microscopy. The clusters have discrete diameters, corresponding to those expected for magic nuclearity of 13, 55, 147, 309, 561, and 1415 and corresponding to closed shells of 1, 2, 3, 4, 5, and 7, respectively. Imaging at different tilt angles has provided confirmation of the spherical nature of these giant clusters. Giant clusters of magic nuclearity have also been found with Pd nanocrystals of ∼ 3.2 nm diameter (nuclearity, ∼ 1415).