Electron impact excitation of the Rydberg states in O2 in the 7–10 eV energy-loss region

Electron impact energy-loss spectra of O2 in the 7–10 eV region has been investigated at low impact energies and high scattering angles. Under these conditions a number of new transitions have been found which do not appear in optical spectra. Bands at 8.595, 8.826, 9.045, and 9.27 eV have been assigned to the 3sσg 1Π (v′=0, 1, 2, and 3) excitations, respectively, and the idenfification of the corresponding 3Πg bands have been reconfirmed. New transitions appearing at 9.13, 9.32, 9.51, 9.58, and 9.78 eV cannot be unambiguously assigned on the basis of the presently available information.