Flash Photolysis and the Recombination of Iodine Atoms

Year: 1957

DOI: 10.7907/Q36G-BS81

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The rate of recombination of iodine atoms in the presence of argon has been redetermined by a flash photolysis technique. The measured rate constant agrees with results obtained by the same method in other laboratories. The recombination rate has also been measured at temperatures up to 548[degrees]K; these results are in accord with shock tube data and with other flash photolysis experiments. The rate is found to decrease slowly with increasing temperature, as about [...].

In experiments at temperatures between 300 [degrees]K and 493 [degrees]K n-butane has been employed as "third body." It is found to be 13 times more efficient than argon at room temperature; this margin decreases as the temperature is raised. The third-body efficiencies of hydrogen and deuterium have been compared at 323 [degrees]K; they are equal.

The above experiments collectively lead to a determination of the rate of the recombination reaction involving I2 itself as third body. This reaction is about 600 times more rapid than that occurring with argon at room temperature, but rapidly becomes insignificant if the temperature is increased. From its temperature dependence [...] Kcal may be deduced for the reaction [...].