Universal features of bonding in metals

Binding-energy-distance relations for metallic systems are shown to exhibit a universal behavior under a simple two-parameter scaling. All currently available ab initio calculations for the cohesion and adhesion of metals, as well as the chemisorption of gas atoms on metal surfaces, are shown to be determined by this single relation. Further, the energetics of diatomic molecules are determined by the same relation, despite the existence of strong volume-dependent forces for metals. These findings suggest a commonality of metallic bonding and a close relationship between molecular and metallic bonding. The universal nature of binding-energy-distance relations implies relations between seemingly disparate physical phenomena. As an example we show that the surface-binding-energy relation can be approximately expressed in terms of the bulk quantities. This leads to an explanation of the well-known empirical result that the surface energy per surface atom is proportional to the cohesive energy per bulk atom. Also, a simple relationship between adsorbate-substrate vibrational stretch frequencies and their desorption energies follows from the universal relationship.