Theoretical predictions of properties of group-2 elements including element 120 and their adsorption on noble metal surfaces

Abstract

Trends in properties of group-2 elements Ca through element 120 and their M(2) and MAu dimers were determined on the basis of atomic and molecular relativistic density functional theory calculations. The relativistic contraction and stabilization of the ns AO with increasing atomic number were shown to result in the inversion of trends both in atomic and molecular properties in group 2 beyond Ba, so that element 120 should be chemically similar to Sr. Due to the same reason, bonding in (120)(2) and 120Au should be the weakest among the considered here M(2) and MAu. Using calculated dissociation energies of M(2), the sublimation enthalpy, ΔH(sub), of element 120 of 150 kJ/mol was estimated via a correlation between these quantities in group 2. Using the M-Au binding energies, the adsorption enthalpies, ΔH(ads), of element 120 of 172 kJ/mol on gold, 127 kJ/mol on platinum, and 50 kJ/mol on silver were estimated via a correlation with known ΔH(ads) in the group. These moderate values of ΔH(ads) are indicative of a possibility of chromatography adsorption studies of element 120 on these noble metal surfaces.

First Principle Based Modeling and Interpretation of Chemical Experiments on Superheavy Element Identification

“…The stability of the net Bader charge of SHE atom and the neighboring Au atoms with respect to increase of n indicated the cluster size used was appropriate. The resulting desorption energies estimates lie within the 1.0 -1.2 eV range for E113 [34] and 2.50 eV for E120 [35], being substantially lower than previously reported values, obtained from simple semiempirical models (1.65 eV for E113 [37] and 3.67 − 3.71 eV [35,38] for E120). More accurate RDFT desorption energies estimates can be used to parametrize semiempirical models.…”

Advances in the Production and Chemistry of the Heaviest Elements

“…Provided suitable long-lived isotopes of these elements are found, the volatility of their atoms might be studied in the long term using some advanced chromatography (e.g., vacuum) techniques that can cope with extremely short lifetimes of their isotopes. To foresee the outcome of such experiments, as well as to study the influence of relativistic effects on the 8s AOs of these heaviest elements and their compounds, some theoretical studies have been undertaken. ,,, For earlier predictions of properties of these elements based on the atomic calculations, see refs and . Properties that are of interest for gas chromatographic studies, i.e., Δ H S 0(298) and Δ H a 0( T ) of elements 119 and 120 on noble metals were predicted on the basis of 4c-DFT calculations for intermetallic M 2 and MAu (M are group-1 and group-2 elements) compounds. , …”

Relativistic and quantum electrodynamic effects in superheavy elements

“…Experimental data for Bi, Hg, Kr, Pb, Po, Rn, Tl, and Xe are taken from Ref. [158], and data for At taken from Ref. [159].…”