Relativistic scattered wave calculations of hexachloro- And hexabromoiridate (IV)

Dirac scattered-wave (DSW) calculations are reported for the ground and several excited states [IrCl₆]^2- and [IrBr ₆]^2-, and comparisons are made to electron spin resonance, optical absorption, and magnetic circular dichorism spectra. Metal and ligand-centered contributions to the Zeeman and hyperfine tensors differ from those estimated from ligand field theory, although both calculations are in qualitative agreement with experiment. The predicted symmetries and spin-orbit splittings of ligand-to-metal charge transfer transitions are approximately correct, but the estimated transitions energies are too low by 0.2-0.7 eV. The implications of this behavior for future relativistic Xα calculations are discussed, with an emphasis on various approximate methods of including spin-polarization effects in relativistic calculations.