Apparent oscillator strengths for molecular oxygen derived from electron energy-loss measurements

Abstract

Oscillator strengths for O2 from 6 to 14 eV are derived from the energy-loss spectrum of 100 eV incident electrons. Integrated f values for the Schumann–Runge bands and continuum, which span four orders of magnitude in intensity, agree well with high-resolution photoabsorption measurements. Vibrational structure superimposed on the Schumann–Runge continuum, previously assigned to the (3sσg) 3Πg Rydberg state, contributes less than 0.5% to the total oscillator strength determined for that region. These data also yield f values for discrete bands in the region between 9.5 and 14.0 eV, where line saturation problems complicate oscillator strength analysis of the optical data. An oscillator strength sum of 0.198 is obtained for all transitions below the ionization potential at 12.07 eV.