The kinetics of the recombination of oxygen atoms at a glass surface

Abstract

Oxygen atoms were produced by electrode and electrodeless discharges in a stream of oxygen, and the concentration distribution in two side arms was studied with probes the tips of which catalyzed the recombination of oxygen atoms. Thermocouples recorded the resulting temperature rise which measures the oxygen atom concentration. The results show that the diffusion of oxygen atoms down the side arm is balanced by a wall removal process which is first order. The fractional collisional efficiency of this process is 1⋅2 + 10 -4 (± 50%) at room temperature and is independent of whether wet or dry oxygen is used. It increases only slightly with rise of temperature. The discharge between internal aluminium electrodes causes a change in the behaviour of the glass surface which may be due to the deposition of aluminium oxide. An electrodeless discharge is therefore to be preferred for the production of oxygen atoms and was used for most of these experiments.