The fact that the melting points of nanoparticles are always lower than those of the corresponding bulk material is a paradigm supported by extensive experimental data for a large number of systems and by numerous calculations. Here we demonstrate that tin cluster ions with 10–30 atoms remain solid at $\sim 50$ K above the melting point of bulk tin. This behavior is possibly related to the fact that the structure of the clusters is completely different from that of the bulk element.

• Received 31 March 2000

DOI:https://doi.org/10.1103/PhysRevLett.85.2530