BRUTE FORCE IN REACTIVE SCATTERING - STERIC EFFECTS IN THE REACTION K+ICL-]KI+CL,KCL+I AT ETR = 3.03 EV

Angular and time-of-flight distributions of products formed in the exothermic reaction K + ICl --> KI + Cl, KCl + I at a collision energy of E(tr) = 3.03 eV and the dependence of these quantities on the orientation of the reagent molecule (brute force method) are reported. KCl and KI are formed with a branching ratio of 10:1 and preferentially scattered into the forward direction of the center-of-mass frame. The KC] flux consists of a slow and a fast component while the data for KI reveal no clear evidence for such a structure. About 57%, 68%, and 60% of the available energy is transferred into the internal degrees of freedom of the fast and slow component of KCl and KI. The fast KCl and the total KI flux exhibit an orientation dependence indicating that collisions of K with the Cl end/I end of ICl favorably lead to KI/KCl. A simple dynamical model based on the harpooning mechanism and the sudden dissociation (explosion) of the molecular ion subsequent to the electron jump is qualified to rationalize the shape of the double-differential reaction cross sections as well as the steric effects. Based on this model, the apex angle of the cones of acceptance and a lower limit for the energy released during the dissociation of ICl- are determined.