An investigation of the second negative system of O2(+) by electron impact

Emission spectrum of O2 from 115 to 300 nm induced by electron impact at 200 eV was obtained using a crossed-beam configuration under optically thin conditions. The second negative system of O2(+) was observed in the range 186-300 nm. Model calculations were performed to derive the contribution made by the second negative system of O2(+) to auroral spectra in the same wavelength range. Observations of the spectral region from 140 to 185 nm, carried out to verify the report of Erdman and Zipf (1986) on the O or O(+) transitions showed no detectable O or O(+) transitions with a cross section upper limit of 10 to the -21 sq cm.