Stratospheric Ozone Conservation By Electron Attachment

The feasibility of recent proposal by Wong to stop stratospheric ozone destruction by converting neutral chlorine atoms into negative ions is investigated with a detailed numerical chemistry model. Two cases, which lead to estimates of the upper and lower bounds of the conversion efficiency, are studied. In the first case, electrons are introduced to a steady state of atmospheric chemical equilibrium. A significant percentage of the electrons is eventually attached to the chlorine atoms to form chlorine ions or water clusters of chlorine ions (Cl
^-
·H
₂
O). In the second case, a plasma of electrons and ions produced by intense microwave ionization of the background neutral nitrogen and oxygen molecules is simulated with a Fokker-Planck code. Because of the large number of electrons lost in recombinations, roughly 1 % of the electrons is predicted to attach to the chlorine atoms. Since the conventional recombination rates we used in the modeling are probably higher than those implied by recent experiments, this may be an underestimate of the actual convertion efficiency.