A Study of Atmospheric Reactions of Neutral Sodium Species and Other Metals of Meteoric Origin

Abstract : The reactions of metallic species introduced into the atmosphere by meteor ablation may play a significant role in mesospheric and stratospheric chemistry. Rate constants for the recombination reactions of alkali atoms with molecular oxygen, K + O2 + M yields KO2 + M and Na + O2 + M yields NaO2 + M, have been measured as a function of temperature from to 300 to 700 K using a fast flow reactor. Laser induced fluorescence is used to monitor the disappearance of Na or K as a function of O2 and M. The reactions are studied in their low pressure third order limit from 1 to 7 torr total pressure with N2, He, and Ar as third bodies. The rate constants are found to have the expected negative temperature dependence. The results are compared with other recent measurements from flame and flash photolysis studies and with theoretical expectations based on an energy transfer RRKM mechanism for the NaO2 activated complex. It has been suggested that the reaction of NaOH with HCl might affect the concentration of odd chlorine, thus having an impact on the ozone balance. This report also describes the first measurement of this reaction rate constant. We have also determined estimates of the same room temperature rate constants.