Gold–superheavy-element interaction in diatomics and cluster adducts: A combined four-component Dirac-Kohn-Sham/charge-displacement study

Abstract

The chemistry of superheavy elements (Z ≥ 104) is actively investigated in atom-at-a-time experiments of volatility through adsorption on gold surfaces. In this context, common guidelines for interpretation based on group trends in the periodic table should be used cautiously, because relativistic effects play a central role and may cause predictions to fall short. In this paper, we present an all-electron four-component Dirac-Kohn-Sham comparative study of the interaction of gold with Cn (Z = 112), Fl (Z = 114), and Uuo (Z = 118) versus their lighter homologues of the 6th period, Hg, Pb, and Rn plus the noble gas Xe. Calculations were carried out for Au-E (E = Hg, Cn, Pb, Fl, Xe, Rn, Uuo), Au7- and Au20-E (E = Hg, Cn, Pb, Fl, Rn) complexes, where Au7 (planar) and Au20 (pyramidal) are experimentally determined clusters having structures of increasing complexity. Results are analysed both in terms of the energetics of the complexes and of the electron charge rearrangement accompanying their formation. In line with the available experimental data, Cn and more markedly Fl are found to be less reactive than their lighter homologues. On the contrary, Uuo is found to be more reactive than Rn and Xe. Cn forms the weakest bond with the gold atom, compared to Fl and Uuo. The reactivity of Fl decreases with increasing gold-fragment size more rapidly than that of Cn and, as a consequence, the order of the reactivity of these two elements is inverted upon reaching the Au20-cluster adduct. Density difference maps between adducts and fragments reveal similarities in the behaviour of Cn and Xe, and in that of Uuo and the more reactive species Hg and Pb. These findings are given a quantitative ground via charge-displacement analysis.

Colloquium : Superheavy elements: Oganesson and beyond

“…Most recent adsorption studies of Cn and Fl on gold surfaces suggest that both elements bind weakly to the surface, i.e., −∆H ads (Au) (in kJ/mol) = 98±3 (Hg) (Soverna et al, 2005), 52 +4 −3 (Cn) (Eichler et al, 2008), ≥48 (Fl) (Yakushev et al, 2014), and 20 (Rn) (Soverna et al, 2005). This is in good agreement with the latest theoretical studies (Pershina, 2018;Pershina et al, 2009Pershina et al, , 2008aRampino et al, 2015). From an empirical relationship between ∆H ads (Au) and the cohesive energy of the bulk material E coh , one estimates E coh = 38 +10 −12 kJ/mol for Cn (Eichler et al, 2008).…”

On the relation between carbonyl stretching frequencies and the donor power of chelating diphosphines in nickel dicarbonyl complexes

“…63,64 In particular, the CD function is defined as a progressive partial integration along a suitable axis z of an electron density difference Δ ρ ( x , y , z ′) The z axis is usually chosen to be the bond axis between the fragments. Accordingly, the CD function at a given point z quantifies the exact amount of electron charge that, upon formation of the bond, is transferred from right to left (the direction of decreasing z ) across a plane perpendicular to the bond axis through z .…”

Diving into chemical bonding: An immersive analysis of the electron charge rearrangement through virtual reality

“…This can be easily achieved by building, for each of the charge‐flow components, the so‐called charge‐displacement (CD) function, Δ q k ( z ), defined as a progressive partial integration along a suitable axis z of the related electron density difference Δ ρ k multiplied by its weight v k (see eq. ), and providing a clear and quantitative picture of the charge flow along a selected direction in space: with the z axis usually chosen to be the bond axis between the fragments. Accordingly, the CD function at a given point z quantifies the exact amount of electron charge that, upon formation of the bond, is transferred from right to left (the direction of decreasing z ) across a plane perpendicular to the bond axis through z .…”