R-MATRIX CALCULATIONS OF LOW-ENERGY ELECTRON-SCATTERING BY OXYGEN MOLECULES

The R-matrix method has been used to study the scattering of electrons by oxygen molecules for impact energies in the range from threshold t o 1 5 eV. Electronic excitation cross sections for transitions to the a1-DELTA(g), b1-SIGMA(g)+, and "6 eV" states of oxygen are presented. Important contributions from a 2-PI(u) resonance, in addition to the w ell-known 2-PI(g) resonance, are found to significantly modify previou s theoretical predictions. Integral elastic scattering cross sections are also obtained for the first time for a complicated open-shell syst em using an ab initio method.