Trajectory study of atomic recombination reactions. VII. Recombination of I and Br atoms

Classical 3-D trajectory investigation of bromine and iodine atom recombination reactions in He, Ar, and Xe, performed earlier, are extended, using an improved sampling technique, to include a larger number of trajectories and a wider temperature range (200–1500 K). The three body potential energy surfaces used were assumed to be nearly additive, but otherwise were defined by the existing molecular beam and spectroscopic data and contained essentially no arbitrary parameters. The agreement between computed and experimental rate constants is reasonable, and is best if the third body is heavy and reaction proceeds via a bound complex, such as IXe. Orbiting inert gas – recombining atom intermediate dimers, XM*, where X = I or Br, contribute to the overall recombination reaction via XM* + X → X2 + M reaction, provided M is heavy. If M = He, this reaction path is negligible at all temperatures studied, again provided that X = I or Br.