Differential and integral cross sections for the electron impact excitation of O₂. I. Optically allowed transitions from the ground state

Electron energy-loss spectra of O2 have been analysed for incident electron energies from 20 to 500 eV, scattering angles from 5 to 130 degrees , and energy losses from 4 to 12.1 eV. Differential and integral cross sections for excitation of the Schumann-Runge continuum, for excited states ranging from 9.7 to 12.1 eV of energy loss, and for elastic scattering have been determined. For the Schumann-Runge continuum oscillator strengths have been calculated from the data. Integral cross sections for the Schumann-Runge continuum as a function of impact energy are compared to theoretical calculations. Differential cross sections for electrons elastically scattered by O2 in the 200-500 eV impact energy range agree well with the observed values by Bromberg (1974) and with calculations utilising the independent-atom mode.