Hybrid density functional theory (DFT) and post-Hartree-Fock methods are compared by depicting potential energy curves of the O-O dissociation of hydroperoxide and the M-O dissociation of transition-metal oxides. The former approach includes BLYP, B2LYP, B3LYP, and more general hybrid DFT methods, while the unrestricted Hartree-Fock (UHF) coupled-cluster (UCC) SD(T) method is considered as the latter approach. The hybrid DFT methods can reproduce the potential curve of the O-O dissociation process and the dissociation energy of HOOH by UCCSD(T). The methods are also useful for depicting potential curves of copper oxide (CuO) and manganese oxide (MnO), and reproduce the experimental M-O binding energies. The nature of Mn-O bonds in the naked Mn-O, Mn-O porphyrine system and model complexes, XH3Mn(IV)O2Mn(IV)H3Y (X,Y = O,H), are examined in relation to the possible mechanisms of oxygenation reactions. It is found that the radical character of Mn-O bonds increases with the increase of the oxidation number of the Mn ion in these systems.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry