Critical Size of a Crossover from Noncrystalline Icosahedra to Crystalline Cuboctahedra Structure for Copper Clusters

We present an estimation of a critical size of a crossover from icosahedral to bulk-like (cuboctahedral) structures for copper clusters by a semi-empirical calculation of cohesive energies for both icosahedral and cuboctahedral copper clusters. The results are consistent with available experimental observations.