Electron Attachment and Ionization in Oxygen, Carbon Monoxide and Carbon Dioxide

Abstract

Electron attachment and ionization cross section measurements have been made under single collision conditions both by an absolute and a comparative method, and are compared with recent relevant data. The corrections employed in the latter are seen to be valid in view of the good agreement with the absolute measurements. In the absolute measurements a Tate and Smith type apparatus is used where all the ions are collected and the measurements do not involve any kinetic energy or angular discriminations. Ionization cross sections for 80 eV electrons in the three gases oxygen, carbon monoxide and carbon dioxide are 2 76 × 10-16 cm2, 2.93 × 10-16 cm2 and 4.23 × 10-16 cm2 respectively, while the peak resonance attachment cross sections resulting in the formation of O- are 1.32 × 10-18 cm2, 2.18 × 10-19 cm2, 1.37 × 10-19 cm2 and 4.44 × 10-19 cm2 at 6 7, 10.1, 4 45 and 8.15 eV respectively. The value 1.37 × 10-19 cm2 at 4.45 eV corresponds to a second peak observed in carbon dioxide. Ionization potentials corresponding to the formation of positive ions and the onset potentials corresponding to the formation of negative ions in the dissociative process have been determined.