Observation of electronically excited states of tetraoxygen.

We have investigated electron transfer to O4+ in reactions with O2, NO, and Cs. We observe formation of O4 molecules that decay by predissociation and by direct dissociation. The kinetic energy release in dissociation as well as the nature of the dissociation products are determined. Evidence for three short-lived electronic states of tetraoxygen at energies near 2 eV above O2+O2 is obtained in electron transfer from O2 and NO. In the experiment with cesium we find evidence for longer-lived electronic states (10-13≤τ≤10-7 s) at 9.4 and 10.5 eV. The energy release and symmetry of the dissociation pattern suggests that the high lying states are symmetric molecular configurations at extended bond lengths (∼2.4 Å). [ABSTRACT FROM AUTHOR]