Relativistic effects on atomic and molecular properties of the heaviest elements

Abstract

Interaction of superheavy element 112 and its homolog Hg with inert and gold surfaces was studied on the basis of atomic and molecular fully-relativistic (4-component) DFT electronic structure calculations. Performance of additional non-relativistic calculations allowed one to demonstrate the role and magnitude of relativistic effects on adsorption energies and bond distances of the studied systems. For example, on quartz, element 112 will be stronger adsorbed than Hg by about 5 kJ/mol (or at 5 degrees higher temperatures) due to the stronger van der Waals interaction. This is caused by the relativistically contracted smallest atomic radius of element 112. Non-relativistically, the trend would be opposite. On surface of gold, element 112 will be about 20 kJ/mol weaker adsorbed than Hg (i.e., it will be deposited at about 100 degrees lower temperatures than Hg). Such a decrease in ΔHads comes at the account of the weaker interaction of the relativistically stabilized 7s1/2(112) orbital with valence orbitals of gold. Still, the relatively large adsorption energy of element 112 is indicative that it is a transition metal forming intermetallic compounds with Au and other metals due to the involvement of the relativistically destabilized 6d orbitals. The influence of relativistic effects on the adsorption energy depends, however, on the adsorption position.