Characterizing fluorine and chlorine atom flow rates using iodine atom spectrometry

The production of F and Cl atoms in an electrical discharge of F-2 or Cl-2 has been examined in a flow reactor. A tunable diode laser was used to prob e the concentration and translational temperature of I atoms produced by F and Cl atom reactions with HI. Kinetic modeling codes were used to determin e the discharge efficiencies from the titration plots and the observed tren ds fur atom concentration as a function of F-2 or Cl-2 and pressure. These calculations indicate that the de discharge used in these experiments is 10 0% efficient for F-2 flow rates less than or equal to0.5 mmol s(-1) and rea ctor pressure less than or equal to 20 torr. The highest F-2-free F atom Ro w rate that we can generate is 1.0 mmol s(-1). Preliminary data for the Cl- 2 discharge indicate that this is a much less efficient source of Cl atoms with yields of less than 50%.