Dynamics of endoergic substitution reactions. II. Br + -> Cl +
We have extended the crossed beams studies described in the preceding paper to the reactions of Br atoms with 1,1- and trans-dichloroethylene.The shapes of the product translational energy distributions and excitation functions for both reactions support our previous conclusion that Cl elimination from Br-R-Cl collision complexes can compete with Br elimination only in the limit that few vibrational modes of the complex are active in energy redistribution.The substitution cross section for the Br + CH2CCl2 reaction is considerably lower than that for the Br + trans-CHClCHCl reaction in the collision energy range 15-25 kcal/mol, suggesting that steric effects play a dominant role in determining the relative magnitudes of the cross sections.
Robinson, Gary N.,Continetti, Robert E.,Lee, Yuan T.