Crossed molecular beam studies on the reaction dynamics of O(D-1)+N2O

Abstract

The reaction of oxygen atom in its first singlet excited state with nitrous oxide was investigated under the crossed molecular beam condition. This reaction has two major product channels, NO+NO and N-2+O-2. The product translational energy distributions and angular distributions of both channels were determined. Using oxygen-18 isotope labeled O(D-1) reactant, the newly formed NO can be distinguished from the remaining NO that was contained in the reactant N2O. Both channels have asymmetric and forward-biased angular distributions, suggesting that there is no long-lived collision complex with lifetime longer than its rotational period. The translational energy release of the N-2+O-2 channel (f(T)=0.57) is much higher than that of the NO+NO channel (f(T)=0.31). The product energy partitioning into translational, rotational, and vibrational degrees of freedom is discussed to learn more about the reaction mechanism. The branching ratio between the two product channels was estimated. The (N2O)-N-46 product of the isotope exchange channel, O-18+(N2O)-N-44 -> O-16+(N2O)-N-46, was below the detection limit and therefore, the upper limit of its yield was estimated to be 0.8%. (c) 2006 American Institute of Physics.