Electron detachment cross section of H ⁻ induced by collisions with O ₂

Abstract We present measured electron detachment cross sections from hydrogen anion induced by collisions with O 2 in the energy range of 1 to 9 keV with two methods, the beam attenuation and the signal growth rate. Processes involved in the interaction are discussed in terms of the cross section differences as a function of the time of flight of the H − through an analysing electric field. As a consequence, an ansatz value of the life-time for the auto-detaching states of H − population of 39 ± 12 ns is derived that is consistent with predictions for the lifetime of the (2 p 2 ) 3 P state of H − .