Theoretical investigations of the heaviest elements: benchmark accuracy and reliable uncertainty

The aim of the research presented in this Thesis is ab initio high accuracy investigations of atomic and molecular properties of heavy and superheavy elements. State of the art relativistic coupled cluster approach is applied to calculations of ionization potentials and electron affinities of these atoms and molecular properties of the compounds that they form. The important effects of relativity were investigated in depth for these heavy species. We have performed extensive investigations of the effect of the various computational parameters on the calculated properties, which allowed us to devise a reliable scheme for assigning realistic uncertainties on our predictions. The results of the research will assist in the challenging experimental investigations of the heavy and superheavy elements and provide new knowledge on the influence of relativity on electronic structure and properties