New survey of electron impact cross sections for photoelectron and auroral electron energy loss calculations

Newly surveyed sets of energy loss cross sections are presented for N-2, O-2, and 0. The work was motivated by a number of new electron energy loss measurements in the late 1980s and early 1990s and recent selected review articles. Each set includes a total ionization cross section and excitation cross sections that correspond to all important non-ionizing energy loss channels for that species. A total cross section for each species is constructed by summing the elastic scattering cross section with the ionization and excitation cross sections. The sum is compared to a measured total cross section obtained from electron transmission experiments. Good agreement is achieved for each of the three species. A loss function is also constructed for each species and compared with the Bethe formula above 100 eV. Good agreement is also achieved in energy loss which is dominated by ion and secondary electron production. Fluxes of photoelectrons and auroral electrons have been calculated for the new sets of energy loss cross sections as well as our previous sets. No substantial differences occur using the new description of energy loss. (C) 1997 American Institute of Physics and American Chemical Society.