Production of vibrationally autodetaching O-2(-) in low-energy electron impact on ozone

Attachment of electrons with energies of 1.2 to 2 eV to ozone was found to lead to the production of O and vibrationally excited O-2(-), the latter subsequently lose electrons by vibrational autodetachment. This type of electron scattering is intermediate between inelastic electron scattering and dissociative attachment. Spectra of the detached electrons have resolved vibrational structure, which can be assigned to the individual O-2(-)/O-2 vibronic transitions, providing detailed information on the product state distribution. The absolute integral cross section for the production of O-2(-) in vibrational states v' greater than or equal to 4 was found to be substantial, for example at 1.7 eV it is 0.27 x 10(-16) cm(2) (with an error bar of about +0.2 x 10(-16) cm(2) and -0.12 x 10(16) cm(2)). Measurements of the signal onsets permit an independent determination of the dissociation energy of ozone into O and O-2 with the result D-0 = 1.06+/-0.04 eV. Comparison of the peak width of the electrons detached by O-2(-) in this work with the width of peaks of O-2(-) resonances observed in electron-O-2 scattering indicates a moderate degree of rotational excitation in the present process.