On relativistic effects in ground state potential curves of Zn2, Cd2, and Hg2 dimers. A CCSD(T) study

The ground state potential curves of the Zn2, Cd2, and Hg2 dimers calculated at different levels of theory are presented and compared with each other as well as with experimental and other theoretical studies. The calculations at the level of Dirac-Coulomb Hamiltonian (DCH), 4-component spin-free Hamiltonian, nonrelativistic Lévy-Leblond Hamiltonian and at the level of simple Coulombic correction to DCH are presented. The potential curves are calculated in an all-electron supermolecular approach including the correction to basis set superposition error (BSSE). Electron correlation is treated at the coupled cluster level including single and double excitations and noniterative triple corrections, CCSD(T). In addition, simulations of the temperature dependence of dynamic viscosities in the low-density limit using the obtained ground state potential curves are presented.