THE EFFECT OF REAGENT TRANSLATIONAL EXCITATION ON THE DYNAMICS OF THE REACTION H+CL-2-]HCL(V',J')+CL

We use fast time-resolved Fourier transform spectroscopy and low pressure infrared chemiluminescence techniques to determine the product energy distribution in the title reaction. We create the,reagent hydrogen. atoms; with 2.3 eV of translational excitation by photofragmentation of H2S at 193 mm, and observe the time evolution of the infrared chemiluminescence from the product HCl(v',J') under single gas kinetic collision conditions. The initial vibrational distribution, determined from the first observation after creation of the H atoms is P(v' = 1:2:3:4:5:6:7:8) = 1.0:0.84:0.74:0.59:0.34:0.24:0.17:0.13. The initial HCl rotational distribution in each vibrational level is broad, showing no identifiable maximum. The fraction of the total available energy entering HCl vibration and rotation, respectively, are 0.19 and 0.10. The time evolution of the observed vibrational and rotational distributions gives information about the changes in the reaction dynamics consequent on reduction of the reagent translational energy.