Absolute Total Electron Detachment and Relative Ionisation Cross Sections for O2 − Collisions with O2 in the Energy Range (10–1500 Ev)

Absolute total electron detachment cross for O2 − collisions with O2 are reported for impact energies ranging from 10 to 1600 eV as measured with a transmission-beam experimental apparatus. The primary anionic beam projectile is produced in a hollow cathode discharge-induced plasma, and the collisions with the neutral molecular target occur in a gas cell at a well-known constant pressure. The accurate determination of the gas pressure (within 8%) in the scattering chamber allowed us to clarify the important discrepancies (by about a factor 4) prevailing between previous total electron detachment cross-section measurements. Additional local maxima in the cross-section values, not previously observed, have been detected around 50 and 150 eV.