The temperature dependence of absolute rate constants for the F+H2 and F+D2 reactions

Abstract

Multiphoton dissociation of SF6 has been used to generate a transient concentration of fluorine atoms in mixtures with argon and H2 or D2. Absolute rate constants for the F+H2 and F+D2 reactions have been determined as a function of temperature by monitoring the appearance rate of HF or DF product chemiluminescence. In the temperature range from 190 °K to 373 °K the results are fit by the expressions kH=1.0×10−10 exp(−(860±100)/RT) and kD=9.1×10−11 exp(−(1100±100)/RT), both in cm3 molecule−1 sec−1. These values are in rough agreement with those obtained recently using a similar technique. The value of the isotope effect kH/kD is in good agreement with two previously determined values.