Efficacy of Density Functionals and Relativistic Effective Core Potentials for Lanthanide-Containing Species: The Ln54 Molecule Set.

The utility of 22 density functionals paired with relativistic effective core potentials (RECPs) for the prediction of thermodynamic properties was investigated for the Ln54 set of lanthanide-containing molecules. The Ln54 set includes lanthanide oxides, fluorides, and chlorides with the lanthanide formally in the +1, + 2, or +3 oxidation state. The density functionals were chosen to span the gamut of complexity from the local density approximation to double hybrids. Computed enthalpies of formation and bond dissociation energies were compared to experimental data and to previous calculations performed with all electron basis sets. The performance of the functionals was then assessed for each class of molecules in the Ln54 set. Overall, SVWN was found to be the best-performing functional having the lowest MAD of 22.1 kcal mol-1 and the most systematic deviation in comparison to the other functionals.