The Behaviour of Free and Attached Electrons in Oxygen

Abstract

The behaviour in oxygen of swarms of electrons having mean energies of up to 2 eV has been studied. Confirmation of the occurrence in oxygen of a three-body attachment process has been obtained, and the attachment coefficient has been measured for 0.04 < E/p < 6 V cm?1 torr?1. Values of the Townsend energy factor k1 have also been obtained over the same range of values of E/p. It was observed that at least three species of negative ions were formed either directly by the electron attachment processes or through secondary collisions between these primary ions and the gas molecules. The mobilities of the various ion species were determined over the range 0 < E/p = 20. The ions were found to have zero-field mobilities of 3.01 ±0.04, 2.52 ± 0.04, and 2.39 ± 0.04 cm2 V?1 s?1. The results obtained for the ion mobilities, the attachment coefficient, and the Townsend energy factor have been compared with those obtained in other investigations.