Slow-Electron Scattering by Atomic Oxygen

The collision cross section of slow electrons in atomic oxygen has been deduced from simultaneous measurements of the dc conductivity and the microwave absorption coefficient of a predominantly atomic oxygen gas mixture in a shock tube. The results showed that the Maxwell-averaged cross section attributable to atomic oxygen must be about 1.5×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ at an electron temperature of 4000°K (mean thermal energy ∼0.5 ev). Elaborating on the theoretical method of Klein and Brueckner, we find that this value is not inconsistent with the photodetachment cross section of negative oxygen ions measured by Branscomb and co-workers.