Vibrationally resolved photofragment spectroscopy of FeO⁺

We report the first vibrationally resolved spectroscopic study of FeO⁺. We observe the 0←0 and 1←0 bands of a ⁶∑←X⁶∑ transition at 28648.7 and 29311 cm^-1. Under slightly modified source conditions the 1←1 transition is observed at 28473 cm^-1. In addition to establishing an upper limit D₀^o(Fe⁺-O)≤342.7 kJ/mol, our results give the first experimental measurements of the vibrational frequencies in both the ground state, v″₀ = 838±4 cm^-1, and the excited electronic state, v′₀ = 662 ± 2 cm^-1. Partially resolved rotational structure underlying the vibrational peaks has been analyzed to measure the predissociation lifetime and estimate the change in molecular constants upon electronic excitation.