Vibrational resolved photoelectron imaging and theoretical study of the group IVB transition metal oxides anions: MO2− (M=Ti, Zr, and Hf)

The vibrational resolved spectra of MO2−/MO2 (M=Ti, Zr, and Hf) are reported by using photoelectron imaging and theoretical calcula-tions. The results indicate that all the ground states of anionic and neutral MO2 (M=Ti, Zr, and Hf) compounds are formed in bent in-sertion structures. The observed ground-state adiabatic detachment energy (ADE) is measured to be 1.597±0.003, 1.651±0.003, and 2.119±0.003 eV for TiO2−, ZrO2−, and HfO2−, respectively. The vibrational frequencies of the anionic and neutral MO2 are also determined from the experimental spectra. The results of theoretical calculations show that the electronic configurations of MO2− are 2A1 with C2v point group. Bond order analysis indicates that the two M−O bonds are all multiple characters.