The effect of atomic oxygen on the vibrational relaxation of molecular oxygen
Quy, Richard Byron
Glass, Graham P.
Master of Arts
The vibrational relaxation of oxygen in the presence of oxygen atoms has been studied in shock waves over the range of 1000° to 3400°K. The experimental section of a shock tube doubled as part of a discharge flow system in which 0 atoms were generated by 02 dissociation in a radio frequency discharge. Concentrations of 0 atoms were measured by monitoring the air afterglow produced in the reaction of NO with 0 atom, and relaxation of the oxygen was followed densitometrically with a laser schlieren technique. Experimentation showed that relaxation data obtained in the flowing system agrees with those obtained in static systems, and that the presence of small quantities of oxygen atoms markedly reduces oxygen relaxation times. Analysis of the data produces the simple expression PTO2-0 = (2.48 + 0.19) X 10-8 - (2.18 + 8.34) X 10-13 T (atm-sec.) for the relaxation time of oxygen dilute in an atmosphere of oxygen atom. It is concluded that the reduction of relaxation time is related to a strong chemical effect in the system. Correlation of these results with published work appears to favor an atom exchange mechanism over a mere atom-molecule interaction although this study is not extensive enough to be unambiguous in this respect.