Ab initio study of palladium dichloride PdCl2 and its anion PdCl2

Abstract We theoretically study geometries and electronic structures of palladium dichloride PdCl2 and its anion PdCl2−, using the MP2 (or CASPT2) and MRCI methods. Spin singlet and triplet PdCl2 and doublet PdCl2− are investigated. As a result of geometry optimization, both linear and bent geometries are obtained for singlet and triplet PdCl2 and only linear geometries for doublet PdCl2−; it is found that there are two minima (linear and bent) on the ground 11A1 state for singlet PdCl2 and the bent minimum is energetically lowest in neutral PdCl2. It is of great importance to note that the total energies of all calculated states for linear PdCl2− are predicted much lower in energy than the ground 11A1 state for linear singlet PdCl2, indicating that the PdCl2− anion is electronically stable. The equilibrium electron affinity of bent 11A1 PdCl2 is calculated 4.61 (4.10) eV with the MRCI (MRCI + Q) method.