Transition state dynamics of F + ICl, C2H5I reactive scattering

Reactive scattering of F atoms with ICl and C2H5I molecules has been studied at an initial translational energy E ∼ 12 kJ mol-1 using a supersonic beam of F atoms seeded in Ne buffer gas. The centre-of-mass angular distribution of IF scattering for F + ICl, measured previously at E ∼ 34 kJ mol-1, shows peaking mainly in the forward direction, which is consistent with reaction via a short-lived complex with a lifetime of half a rotational period. The microcanonical theory for dissociation of a persistent complex via a prolate symmetric top transition state accounts for the higher energy F + ICl scattering arising from the full range of impact parameters. The angular distribution for F + C2H5I shows peaking in the forward and backward directions which is consistent with a complex lifetime greater than one rotational period. The extended microcanonical theory accounts for scattering by a range of transition state configurations generated by internal rotation about the extended C-I bond for collisions at the ...