Radical-radical reaction dynamics: A combined crossed-beam and theoretical study

We present an overview of our recent studies of the gas-phase reaction dynamics of O(³P) with a series of hydrocarbon radicals [allyl (C₃H₅), propargyl (C₃H₃), t-butyl (t-C₄H₉)] as prototypal radical-radical oxidation reactions. High-resolution laser spectroscopy in a crossed-beam configuration was applied to examine the nascent rovibrational state distributions and Doppler profiles of the reactive scattering products. The analyses of the product energy and population distributions demonstrated the existence of unusual dynamic characteristics and competition between the addition and abstraction reaction mechanisms at the molecular level. These features, which are in sharp contrast with those of the oxidation reactions of closed-shell hydrocarbon molecules, are discussed with the aid of ab initio and quantum statistical calculations.