THE STUDY OF ELECTRICALLY DISCHARGED O 2 BY MEANS OF AN ISOTHERMAL CALORIMETRIC DETECTOR

Abstract

Molecular oxygen was subjected to an electrodeless discharge in the pressure range 0.1–3 mm Hg. The oxygen atom concentration was measured as a function of time in a flow system by means of a movable atom detector which consisted of a platinum wire coated with a suitable catalyst for atom recombination. The atom concentration was calculated from the heat liberated when the detector was operated under isothermal conditions. The surface recombination was found to be first order in the atom concentration. A value of 7.7 × 10 −5 was obtained for the recombination coefficient (γ) on Pyrex. No temperature dependence for γ was observed. The gas phase recombination of oxygen atoms was found to be consistent with the mechanism[Formula: see text]The rate constant for the third-order reaction was found to have a value of 1.0 × 10 14 cc 2 mole −2 sec −1 , and a small negative temperature dependence.Evidence was also obtained for the presence of considerable amounts of excited molecular oxygen in electrically activated O 2 .