Zur O 2 ‐Dissoziation in der Gleichstromglimmentladung. Teil I Bestimmung des Dissoziationsgrades mittels der O 3 ‐Bildung an gekühlten Oberflächen

The synthesis of ozone on the surface S cooled with liquid nitrogen O + O 2 ·S→O 3 ·S[1] was used to measure the concentration of atoms in a flow tube downstream of a d.c. discharge. The flow tube was constructed in the form of a U‐tube. The ozone was deposited as a blue liquid film in the neighbourhood of the surface of the liquid nitrogen on the walls of the part of the U‐tube, which was connected with the discharge tube. The oxygen atom decay in the U‐tube was observed by measuring the production of ozone as the distance between the discharge tube (diameter: 5,2 cm) and the surface of the liquid nitrogen was varied. The decay is first order in atom concentration for the pressures p > 1 torr. But for the pressures below p = 1 torr near by the discharge tube we observed deviations from the law of decay In [O] 0 /[O] = k·t for the currents of about i = 100 mA. This effect was attributed to the process\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm O + O + M} \to {\rm O}_{\rm 2} {\rm + M,}} & {{\rm M} = {\rm O}_2 (^3 \sum _g ^ -),{\rm O}_2 (^1 \Delta _g),{\rm O}_2 (^1 \sum _g ^ +).} \\ \end{array} $$\end{document}From the extrapolation of an ozone production curve atom concentrations in the discharge have been obtained. The transition from the „H” form to the „T” form (striated, low average electric field) of the discharge [2] caused the dissociation to decrease rapidly. The highest dissociation (10%) was obtained in the „H” form at high currents ( i = 120 mA) and low pressures ( p = 0,60 torr). The yield of atomic oxygen per kilowatt hour of energy was measured as functions of pressure and gas flow rate for i = 100 mA and i = 50 mA.