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

Abstract

For pt.I see ibid., vol.11, no.22, p.3913 (1978). The electron impact excitation spectrum of O₂ has been studied for the scattering angle range from 10 to 130 degrees and the energy-loss range from 0 to 7.1 eV. Differential and integral cross sections for excitation of the a¹ Delta _g and b¹ Sigma _g⁺ states and a group of states ranging from about 4.5 to 7.1 eV energy loss (broad maximum at 6.1 eV) have been determined in the impact energy ranges E₀=20-200 eV, 20-150 eV and 20-500 eV, respectively. They are the first experimental data on the cross sections for excitation of these states at collision energies larger than 50 eV. The 6.1 eV broad peak is designated as the sum of the excitation to the A³ Sigma _u⁺, C³ Delta _u, and c¹ Sigma _u^- states by virtue of the angular distribution and energy dependence of the differential and integral cross sections.