Data have been compiled on the cross sections for collisions of electrons and photons with oxygen molecules (O2). For electron collisions, the processes included are: total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, dissociation, ionization, and attachment. Ionization and dissociation processes are considered for photon impact. Cross-section data selected are presented graphically. Spectroscopic and other properties of the oxygen molecule are summarized for understanding of the collision processes. The literature was surveyed through August 1987, but some more recent data are included when available to the authors.

Electron impact emission cross sections of Ar were measured for the , and transitions from the threshold to 1000 eV by a polarization-free method. Two different methods were used in determining absolute emission cross sections for the first resonance lines. The first method is to measure the cascade cross sections to the 4s state by detecting visible to near-infrared radiation and the total cascade cross section was then combined with the level excitation cross section to the 4s state to give the emission cross section for the resonance line. The second method is to measure the vacuum ultraviolet sensitivity of the apparatus and an absolute emission cross section for the resonance line was obtained by comparing its spectral intensity with that of the Lyman- radiation produced from by electron impact. The two results showed good agreement within the experimental errors. The level excitation cross sections to the and states were obtained by subtracting the total cascade cross section to these levels from the corresponding emission cross sections.

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