Excitation Mechanism for the O2 Schumann-Runge System

摘要

The Schumann-Runge band system of O2 involving transitions between the X triplet Sigma (g)(-) ground state and the B triplet Sigma(u)(-) excited state has been the subject of many investigations which have shown that the radiating state is strongly coupled to the O-atoms and that the population mechanism is very fast. In the present study, the emitted radiation was monitored with filter-photomultiplier combinations as a function of time behind incident shock waves in O2, O2-Ar, and O2-Ne mixtures at wavelengths centered at 2300 and 3250 A. Initial pressures in the shock tube were 1 to 100 torr and the (equilibrium) temperature range was 2800 to 5300K. The results are in disagreement with the results of Myers and Bartle both in apparent activation energy and absolute magnitude. Various other excitation mechanisms were considered and it was shown that inverse predissociation is the only one which fits the data and that it must dominate over a very wide range of conditions. (Author)