Periodic properties of force constants of small transition-metal and lanthanide clusters

An overview is given on existing experimental data with the aim of understanding periodic trends in metal bonding and to gain insight on the degree to which properties of small clusters can be examined for understanding comparable properties in larger clusters. The focus is almost entirely on experimental properties of homonuclear clusters with an emphasis on force constants. As such, data on the restoring force for small metal clusters are obtained for almost all transition-metal dimers as well as many trimers and several higher clusters.