High-Level Ab Initio Calculations of Molecular Properties of Chromium Monocarbonyl, CrCO

Chromium monocarbonyl (CrCO) is the simplest unsaturated transition metal carbonyl, and ab initio methods that include a dynamic electron correlation effect are necessary to calculate the molecular properties of CrCO. We employed post Hartree-Fock ab initio methods with various all-electron basis sets to calculate the molecular properties of CrCO including the molecular structures, vibrational frequencies, and bond dissociation energy. The methods including triple excitation and a quadruple-zeta level basis set are required to reasonably describe themolecular properties of CrCO. Wefound that the most efficient combination of theoretical method and basis set for this weakly interacting system is the unrestricted coupled-cluster singles and doubles with perturbative triples (UCCSD(T)) with the Sapporo-DKH3-QZP basis set.