Photoelectron spectroscopy and density functional theory study of ConO− (n = 1–3)

ConO− (n = 1–3) clusters were investigated with photoelectron spectroscopy and density functional calculations. The vertical detachment energies (VDEs) of ConO− (n = 1–3) were measured to be 1.54 ± 0.04, 1.43 ± 0.08, and 1.42 ± 0.08 eV respectively from their photoelectron spectra. The electron affinity and term energy of CoO were determined to be 1.54 ± 0.04 eV and 0.31 ± 0.04 eV respectively based on the vibrationally resolved photoelectron spectrum of CoO− and theoretical calculations. The structures of ConO− (n = 1–3) were determined by comparison of photoelectron experiments and calculations. The analysis of molecular orbitals shows that the HOMOs of ConO− (n = 1–3) cluster anions are mainly localized on the Co atoms.