Nuclear Magnetic Resonance parameters of mercury atom and water molecule complex: Relativistic calculations

Potential energy surface of the (HgH2O)-H-center dot center dot center dot dimer was studied by means of CCSD(T) and DFT methods. After that nuclear shielding constants and nuclear spin-spin coupling constants have been calculated at the DFT level. All the calculations were carried out with four-component relativistic Dirac-Coulomb Hamiltonian. DFT produces a global minimum with mercury atom on C-2v axis of water molecule, but this is not confirmed by CCSD(T). All of the calculated shielding constants increase with the increase in the distance between mercury and oxygen atoms. sigma(Hg) at equilibrium geometry is 12 ppm smaller than in isolated mercury atom.