Direct Detection of Oxygen 1D2 Atoms by Mass-Resolved, Resonance-Enhanced Multiphoton Ionization Spectroscopy, following Ozone Photolysis at ∼276 nm

Singlet atomic oxygen Rydberg states of the ( 2 D) 3d‘ configuration have been observed as three-photon resonances. The states lie above the first ionization energy but are forbidden to autoionize in LS coupling. All transitions originated from the metastable p 4 1 D 2 state produced by laser photolysis of ozone at ∼276 nm. The same laser pulse was used to ionize the atoms. Arrival time spectra of the atomic photofragment have also been recorded.