Absolute partial cross sections for electron-impact ionization of CO2 from threshold to 1000 eV

Absolute partial cross sections for the production of CO2+, CO+, CO22+, O+, C+, O2+, and C2+ from electron-impact ionization of CO2 are reported for electron energies from threshold to 1000 eV. The product ions are mass analyzed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output provides clear evidence that all product ions are completely collected. The overall uncertainty in the absolute cross section values is +/-3.5% for singly charged parent ions and is slightly greater for fragment and doubly charged ions. For the fragment ion cross sections, all but one of the previous measurements are observed to be significantly lower than the present results. (C) 1996 American Institute of Physics.