Relativistic effects in mercury: Atom, clusters, and bulk

We study the effects of relativity on the electronic structure of Hg as it evolves from an atom to a cluster, and then to the bulk. A comparison of nonrelativistic and scalar-relativistic results for bulk Hg, obtained self-consistently, clearly shows the importance of including the relativistic terms as well as treating the 5d electrons as valencelike. Our cluster calculations show that the relativistic effects are equally important for clusters, and that the differences in many electronic properties such as the size dependence of the gap energy and the l character of Hg clusters with respect to other divalent-metal clusters, for example, Be and Mg, arise due to the relativistic terms, thus providing further insight into the electronic origins of these properties.