The rate of homogeneous recombination of fluorine atoms

Abstract

The recombination rate of fluorine atoms has been determined in a Teflon-coated flow reactor at 295°K and pressures of 10–81 torr with Ar as the carrier gas. Concentrations of atomic fluorine are measured by titrating with Cl 2 and using the intensity of chlorine atom recombination emission as an endpoint indicator. The data is fit with a third-order homogeneous recombination rate constant of 2.9 × 10 13 cm 6/mole 2sec. Possible systematic errors in the titration lead us to claim only a factor of two accuracy for the result. The measured rate constant is ca. a factor of 10 less than values calculated by two different theories and ca. a factor of 100 less than the accepted rate constants for homogeneous recombination of most other atoms under similar conditions.