RELATIVISTIC CALCULATIONS ON PLATINUM HYDRIDE USING EFFECTIVE CORE POTENTIALS AND 1ST-ORDER PERTURBATION-THEORY

Ab initio relativistic calculations have been performed for the two lowest electronic states of the PtH molecule, with relativistic effects accounted for by means of relativistic core potentials and first-order perturbation theory. Electron correlation has been treated at the multireference configuration interaction level. The (2)SIGMA and (2)DELTA states are close in energy, with the SIGMA state somewhat lower, according to the core potential calculations. It is concluded that a method which gives a correct atomic description is imperative to describe the spectroscopy of the molecule.