Reactive scattering of a supersonic fluorine-atom beam: F + C2H5I, C3H7I, (CH3)2CHI

Reactive scattering of F atoms with C2H5I, C3H7I and (CH3)2CHI molecules has been studied at an initial translational energy E ≈ 38 kJ mol-1 using a supersonic beam of F atoms seeded in He buffer gas. Centre-of-mass angular distributions of IF scattering show peaking in the forward and backward directions, which is consistent with reaction via persistent F-I-C2H5, F-I-C3H7 and F-I-CH(CH3)2 complexes with lifetimes greater than two rotational periods. The extended microcanonical theory indicates that the angular distribution of reactive scattering for F + C2H5I arises from a range of transition state configurations generated by internal rotation about the extended C-I bond. The reactive scattering for F + C3H7I arises from a wide range of transition-state configurations, with sharply peaked forward and backward scattering from extended configurations and mildly peaked scattering from more contracted configurations. However, the range of transition-state configurations is much more limited for F + (CH3)2CHI...