Role of Renner Teller and Spin−Orbit Interaction in the Reactive Scattering of O(3P) Atoms with CF3I Molecules

Abstract

Reactive scattering of O(3P) atoms with CF3I 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 3A‘‘ potential energy surface, while the forward and backward peaked scattering is attributed to dissociation of a persistent singlet OICF3 complex formed by intersystem crossing to the underlying 1A‘ potential energy surface. The direct scattering over the triplet 3A‘‘ 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 3A‘‘ potential energy surface. This dynamical behavior is correlated with the effect of charge transfer interaction of the form OI+R- on Renner Teller splitting of the triplet potential energy surface.