Angular distribution rebound reactions

Two other contributions (Grice, 1970 Grice and Hardin, 1971) have also incorporated orientation effects in an impulsive model, in this case involving only two hard spheres, which was applied to the alkali-iodine molecules M + RI rebound reactions. Experimental results on the 0+ + H2/D2/HD reaction have been compared (Gillen et al 1973) to predictions of a sequential encounter model that also represents the atoms as hard spheres. Product angular distributions and their isotopic dependences are well represented by the model, which however, is less useful in predicting collision energy behaviours. 

Passing to direct reactions, the stripping reactions are more readily treated theoretically than rebound reactions. In particular, it has been found that in many stripping reactions of the type A + BC AB + C the transfer of atom B from molecule BC to AB does not involve recoil. Por such spectator-stripping reactions (C is the spectator), angular and energy distributions of products can be readily calculated, thus permitting a simple verification of the assumption on the reaction mechanism. 

Figure 4.14 shows a comparison of the two angular distributions corresponding to the two Kl-forming reactions. We note that the entire backscattered cross-section for the KI from the rebound reaction of K -i- ICH3 fits under tiie backward... 

We focus our attention on the DIPR (direct interaction with product repulsion) model and its variant, the DIPR-DIP model, mainly because it can be used to predict an entire range of dynamic observables in chemical reactions angular and recoil velocity distributions, rotational energy and orientation and vibrational energy of the reaction products. It is also able to account for the switch from the rebound to the stripping reaction mechanism for a given system when the collision energy is increased. The beauty of the model is its ability to include semiempirical parameters, each of which is related to a different physical phenomenon. 

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