Andréi Zaitsevskii

Importance of spin-orbit effects on the isomerism profile of Au3: An ab initio study

Two-component relativistic density functional theory combined with high-level ab initio correlation techniques was applied to the study of the electronic structure and isomerism of Au(3). All calculations were performed with accurate small-core shape-consistent relativistic pseudopotentials. Density functional theory was used to determine the equilibrium structures of the Au(3) isomers and isomerization path and to estimate the contributions of spin-orbit effects to the ground state electronic energy along the path. The reliability of these estimates was verified through independent many-body multipartitioning perturbation theory calculations. Spin-orbit corrections were used to refine the isomerization energy profile computed by spin-orbit-free coupled cluster methods.

Relativistic effective core potential calculations of Hg and eka-Hg (E112) interactions with gold: Spin-orbit density functional theory modeling of Hg–Aun and E112–Aun systems

Interactions of eka-Hg (E112) and Hg atoms with small gold clusters were studied in the frame of the relativistic effective core potential model using the density functional theory (DFT) approach incorporating spin-dependent (magnetic) interactions. The choice of the exchange-correlation functional was based on a comparison of the results of DFT and large-scale coupled cluster calculations for E112Au and HgAu at the scalar relativistic level. A close similarity between the E112Aun and HgAun equilibrium structures was observed. The E112 binding energies on Aun are typically smaller than those for Hg by ca. 25%-32% and the equilibrium E112-Au separations are always slightly larger than their Hg-Au counterparts.

Ab initio study of Hg-Hg and E112-E112 van der Waals interactions

The ground electronic state of the eka-mercury dimer (E1122) was studied within the model of generalized relativistic effective core potentials. A combined procedure based on describing correlation effects by the scalar relativistic coupled-cluster method and on taking into account spin-dependent interactions by means of density-functional theory was used in the calculations. A high accuracy of this approach was confirmed by the results of similar calculations for the mercury dimer. It was found that the bond length is nearly 0.4 Å shorter in E1122 than in Hg2 and that the dissociation energy of the former is approximately twice as high as that of the latter dimer.

Estimating the adsorption energy of element 113 on a gold surface

We report first-principle based studies of element 113 (E113) interactions with gold aimed primarily at estimating the adsorption energy in thermochromatographic experiments. The electronic structure of E113-Aun systems was treated within the accurate shape-consistent small core relativistic pseudopotential framework at the level of non-collinear relativistic density functional theory (RDFT) with specially optimised Gaussian basis sets. We used gold clusters with up to 58 atoms to simulate the adsorption site on the stable Au(111) surface. Stabilization of the E113-Aun binding energy and the net Bader charge of E113 and the neighboring Au atoms with respect to n indicated the cluster size used was appropriate. The resulting adsorption energy estimates lie within the 1.0–1.2 eV range, substantially lower than previously reported values.

First principles based modeling of the adsorption of atoms of element 120 on a gold surface

Interactions of single atoms of element 120 (E120) and its lighter homologs (Ba and Ra) with the stable gold (111) surface simulated by clusters are studied using relativistic density functional theory and accurate two-component shape-consistent small-core pseudopotentials. The predicted E120 adsorption energy on gold (ca. 250 kJ mol(-1)) is significantly larger than the previously reported value. The trends in interactions of heavy group 2 elements with gold are discussed on the basis of electronic structure calculations and estimates by the semiempirical macroscopic Eichler-Miedema model.