Importance of spin-orbit effects on the isomerism profile of Au3:: An ab initio study

Two-component relativistic density functional theory combined with high-level ab initio correlation techniques was applied to the study of the electronic structure and isomerism of Au-3. All calculations were performed with accurate small-core shape-consistent relativistic pseudopotentials. Density functional theory was used to determine the equilibrium structures of the Au-3 isomers and isomerization path and to estimate the contributions of spin-orbit effects to the ground state electronic energy along the path. The reliability of these estimates was verified through independent many-body multipartitioning perturbation theory calculations. Spin-orbit corrections were used to refine the isomerization energy profile computed by spin-orbit-free coupled cluster methods.