A new band of O+ observed in measurements of angle-resolved translational energy by electron impact on O2

The translational energy distribution of O+ produced by electron impact on O2 has been measured in a supersonic free jet. A new band was observed at 0.2 eV by detection of only the cations flying at a right angle to the jet. The intensity was strongest at 90° to the direction of the electron beam and the appearance energy was 19.4±0.5 eV. It is concluded, on the basis of Dunnʹs selection rule, that the new band originates from the 3Πu-Rydberg series converging to the B 2Σg− state of O2+.