Homogeneous rate of recombination of hydrogen atoms

Abstract

The rate of decay of hydrogen atoms has been measured in a conventional type of discharge-flow system at temperatures between 190–350 °K. The recombination fitted the equation[Formula: see text]where ks is the first order surface rate constant. No three-body recombination for M = H was observed at the low levels of dissociation (2–5%) employed. When the flow gases contained traces of water vapor and (or) oxygen as impurities, the homogeneous rate constants (k2,M) had a small positive activation energy which was due to the influence of a surface reaction between hydrogen atoms and the impurities. In the absence of impurities, true homogeneous rate constants were obtained. A value of k2,Ar = 4.6 ± 0.5 × 1015 cm6 mole−20s−1 was found at 291 °K. The temperature variation was approximately T−1/2 over the range 190–350 °K.