Electron detachment from O2- ions in oxygen: the effect of vibrational excitation and the effect of electric field

Electron detachment from O-2(-) ions has been theoretically studied in oxygen (i) when the gas is vibrationally excited and (ii) when the ions are heated in a strong external electric field. Assuming that electron detachment proceeds via the formation of vibrationally excited temporary O-2(-) ions, the detachment rate was determined on the basis of the statistical approach for the vibrational transfer and relaxation in collisions between O-2(-) ions and O-2 molecules. The approach used in our previous work to study electron detachment in vibrationally excited oxygen was amended to take into account the conservation of total angular momentum in O-2(-)-O-2 collisions. The calculated detachment rates agree well with available measurements in oxygen under equilibrium conditions. The method was used to calculate detachment rates under strongly non-equilibrium conditions in which the vibrational temperature of molecules or ion translational temperature is elevated. The obtained results were compared with available measurements in drift tubes.