Reactive scattering of a supersonic oxygen atom beam: O + CS₂

Abstract

Reactive scattering of O atoms with CS₂ molecules has been studied at an initial translational energy E = 38 kJ mol^-1 using a supersonic beam of O atoms seeded in He and at E = 13 kJ mol^-1 using O atoms seeded in Ne. Velocity distributions of OS product were measured over a wide angular range by cross-correlation time-of-flight analysis. Full contour maps of the differential reaction cross-section have been determined, which show that reaction proceeds by a stripping mechanism unaffected by initial translational energy. A minor but still significant fraction f′ _av = 0·31 of the total available energy is disposed into product translation. The flash photolysis measurements of Smith indicate that only a modest fraction f′ _vib = 0·26 is disposed into vibration and that hence a substantial fraction f′ _rot ∼ 0·4 is disposed into rotation. Qualitative molecular orbital theory offers a rationalization for product rotational excitation in the O + CS₂ reaction.