Systematic Study of Oxo, Peroxo, and Superoxo Isomers of 3d-Metal Dioxides and Their Anions

Abstract

The electronic and geometrical structures of the ground and excited states of the 3d-metal dioxides ScO2, TiO2, VO2, CrO2, MnO2, FeO2, CoO2, NiO2, CuO2, and ZnO2 along with their singly charged negative ions have been calculated using the density functional theory with generalized gradient approximation for the exchange-correlation potential. We have considered oxo, peroxo, and superoxo isomers in both neutral and anionic series. The ground states of all 3d-metal dioxides and their anions possess oxo forms, except for copper dioxide, which prefers a superoxo form. All the dioxides have a large number of isomers closely spaced in total energy. The champion, FeO2 -, possesses five isomers within an energy range of 0.35 eV. The energy gap between oxo, peroxo, and superoxo isomers decreases along the series from TiO2 to ZnO2. ScO2 has peroxo and superoxo isomers which are close in total energy to its oxo ground state. The electron affinities are computed for all types of isomers and are compared to available experimental data. On the average, our theoretical values are within 0.2 eV from the corresponding experimental data. All the ground-state dioxides and their anions are found to be thermodynamically stable except for ZnO2, which is unstable toward dissociation of molecular oxygen.

Bis(cyclopentadienyl)chromium and Bis(cyclopentadienylvanadium) Composites of Mesoporous Niobium Oxide with Pseudo-One-Dimensional Organometallic Wires in the Pores

“…The Hubbard potential U can be calculated from an I of 5.56 eV 41 for cobaltocene and an A estimated from the sum of the A value for cobaltocene and half the difference between the A value for Co(II)O 42 and Co(IV)O), 43 given that the literature A value for Co 2 (III)O 3 is not available. This gives a value of 4.30 eV for U, while W for Co is 4.35 eV.…”

Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2

“…These results indicate that the Si-embedded graphene possesses high thermal stability. [53]. In particular, as shown in Figure S3, the electrons mainly accumulate on O 2 , where O 2 -2p* orbital is half-filled, and the whole graphene structure is still covalent.…”

Communication: A vibrational study of titanium dioxide cation using the vacuum ultraviolet laser pulsed field ionization-photoelectron method

“…9,10 On the theoretical side, predictions on the IE, dissociation energies, molecular geometry, and harmonic vibrational frequencies for TiO 2 (X 1 A 1 ) have also been reported. [11][12][13] However, up to the present no spectroscopic studies on the TiO 2 + cation have been made, and thus the IE(TiO 2 ) and harmonic vibrational frequencies for TiO 2 + are not known. The experimental apparatus used in the present study has been described in detail previously.…”