On the Mechanism of Electron Attachment by O2

Abstract

Fano's theory on configuration mixing was applied to investigate negative oxygen molecular ion formation in low energy (less than 1 eV) electron collision: e+O 2 →O 2 -* . A cross section formula is obtained. It is found essentially equivalent to Breite-Wigner's one-level formula used by Herzenberg. By the evaluation of the transition matrix element, the mechanism of electron capturing process is investigated and the capture cross section has been expressed in a more explicit from. Attention is paid to two types of transition. Landau-Zener type transition can occur at the crossing point between the adiabatic potentials of e+O 2 and O 2 - systems. Another type of transition can occur through the non-adiabatic coupling between the molecular electronic and vibrational states. Either or both of these can play an important role on the transition mechanism. Integrated capture cross section and resonance width of O 2 -* state are found to be 0.012 a 0 2 ·eV and 4 µ eV, respectively, at 82 meV electron impact (fi...