Reactive scattering of O( 3 P) atoms with CF 3 I molecules has been studied at initial translational energies E ∼ 108 and 42 kJ mol -1 using supersonic beams of O atoms seeded in He buffer gas generated from rf and microwave discharge sources. At the higher initial translational energy, the IO scattering shows a broad peak in the forward hemisphere with respect to the initial O atom direction with a product translational energy distribution shifted to higher energy than the prediction of phase space theory. At the lower initial translational energy, the IO scattering shows a sideways peaked component with a fraction f ′ ∼ 0.4 of the total available energy being disposed into translation and a forward and backward peaked component with a product translational energy distribution in accord with the predictions of phase space theory. The sideways scattering is attributed to direct reaction over the triplet 3 A′′ potential energy surface, while the forward and backward peaked scattering is attributed to dissociation of a persistent singlet OICF 3 complex formed by intersystem crossing to the underlying 1 A′ potential energy surface. The direct scattering over the triplet 3 A′′ potential energy surface contributes a fraction, ∼0.5, to the total reaction cross section at the lower initial translational energy, while the forward scattering at the higher initial translational energy is dominated by direct reaction over the triplet 3 A′′ potential energy surface. This dynamical behavior is correlated with the effect of charge transfer interaction of the form OI + Ron Renner Teller splitting of the triplet potential energy surface.

Reactive scattering of OD radicals with ICl and Br2 molecules has been studied at an initial translational energy E ∼ 90 kJ mol-1 using a supersonic beam of OD radicals seeded in He buffer gas generated from a high-temperature radio frequency discharge source. The center-of-mass angular distribution of DOI scattering from OD + ICl shows sharp forward and backward peaking with the relative intensity of the backward peak being lower by a factor ∼0.6 ± 0.1. The DOBr scattering from OD + Br2 shows broader peaking in the forward direction declining to a lower intensity ∼0.8 ± 0.2 in the backward direction. In both cases the product translational energy distributions peak at low energy with a tail extending out to higher energy. Comparison with the predictions of phase space theory indicates that the OD + ICl reaction proceeds via a DOICl collision complex with a lifetime of approximately one rotational period, while the OD + Br2 reaction shows evidence for the migration of the OD radical between the Br atoms of a DOBrBr complex. The DOICl complex corresponds to a significant well of depth E 0 ∼ 80 kJ mol-1 on the potential energy surface for the OD + ICl reaction while the potential energy surface for the OD + Br2 reaction also supports a shallow minimum.