Angular distributions of O+ from O-2(2+) produced by electron impact an O-2

Coincidence measurements of the angular distributions of O+ dissociated from O-2(2+) produced by electron impact on O-2 have been made. With an incident electron energy of 55 eV, 2.6-, 3.7-, 4.5-, and 5.8-eV O+ ions were detected separately using the time-of-flight and coincidence method at selected angles between 40 degrees and 140 degrees in 10 degrees steps. The results show two flat, isotropic and two anisotropic angular distributions and attempts have been made to interpret these symmetries and to identify the sources of the ions.