Spin-orbit effects on magnetically induced current densities in the [formula omitted][formula omitted] clusters.

We report about the spin-orbit effects on the aromaticity of the B 4 2 - , Al 4 2 - , Ga 4 2 - , In 4 2 - and Tl 4 2 - clusters via the magnetically-induced current density method. All-electron density functional theory (DFT) calculations were carried out using the four-component Dirac-Coulomb (DC) Hamiltonian, including scalar and spin-orbit relativistic effects. The relativistic values for ring current strengths were obtained by numerical integration over the current flow. These values were compared to the scalar relativistic and non-relativistic values, in order to assess the corresponding contributions to aromaticity. It was found that in the heavy cluster, Tl 4 2 - , there is a significant influence of both scalar and spin-orbit relativistic effects. [ABSTRACT FROM AUTHOR]