Adsorption of the astatine species on a gold surface: a relativistic density functional theory study

Abstract We report first-principle based studies of the adsorption interaction of astatine species on a gold surface. These studies are aimed primarily at the support and interpretation of gas chromatographic experiments with superheavy elements, tennessine (Ts, Z = 117 ), a heavier homologue of At, and possibly its pseudo-homologue nihonium (Nh, Z = 113 ). We use gold clusters with up to 69 atoms to simulate the adsorption sites and estimate the desorption energies of At & AtOH from a stable gold (1 1 1) surface. To describe the electronic structure of At - Au n and AtOH - Au n complexes, we combine accurate shape-consistent relativistic pseudopotentials and non-collinear two-component relativistic density functional theory. The predicted desorption energies of At and AtOH on gold are 130 ± 10  kJ/mol and 90 ± 10  kJ/mol, respectively. These results confirm the validity of the estimates derived from chromatographic data ( 147 ± 15  kJ/mol for At, and 100 - 10 + 20  kJ/mol for AtOH).