COMPARISON OF RATE CONSTANTS FOR REACTIONS OF HYDROGEN-ATOMS WITH CHLORINE, FLUORINE, IODINE CHLORIDE, AND CHLORINE FLUORIDE

The infrared emission intensities from the HCl and HF products have been used to assign relative rate constants for the reaction of H atoms with Cl2, F2, ClF, and ICl. The experiments were done in a fast flow apparatus utilizing ∼1 torr of Ar carrier gas. The vibrational distributions obtained from analysis of the chemiluminescence recorded with a Fourier transform spectrometer at the first window of the flow reactor were very close to the initial distributions produced by the chemical reaction. Except for a small residue of population in the high J levels of HCl from the H + ICl reaction, the rotational populations had relaxed to a room temperature Boltzmann distribution. The relative rate constants for HCl formation from the F2, Cl2, ClF, and ICl series are 0.053:1.00:1.99:2.42, Since the absolute rate constant is well known for Cl2, these data, plus the vibrational-rotational distributions of product states, give absolute rate constants for formation of individual product quantum states. Summation of the HCl and HF relative intensities from H + ClF gave a macroscopic branching ratio of 5.2 favoring the HCl channel. For the H + ICl reaction, the HI/HCl ratio is <0.5. Dynamical models based upon the data of this and the preceding paper are discussed. © 1979 American Chemical Society.