Dynamics of Inelastic and Reactive Collisions of 16O(3P) with 15N18O.

Abstract

The dynamics of O(3P) + NO collisions were investigated at a collision energy of ⟨Ecoll⟩ = 84.0 kcal mol-1 with the use of a crossed molecular beams apparatus employing a rotatable mass spectrometer detector. This experiment was performed with beams of 16O atoms and isotopically labeled 15N18O molecules to enable the products of reactive and inelastic scattering to be distinguished. Three scattering pathways were observed: inelastic scattering (16O + 15N18O), O-atom exchange (18O + 15N16O), and O-atom abstraction (18O16O + 15N). All product channels exhibited a preponderance of forward scattering, but scattering over a broad angular range was also observed for all products. For inelastic scattering, an average of 90% of the collision energy is retained in the translation of 16O and 15N18O. On the other hand, for O-atom exchange (which also leads to O + NO products), the collision energy is partitioned roughly evenly between the translation of 18O + 15N16O and the internal excitation of 15N16O. The available energy for O-atom abstraction is significantly lower than the collision energy because of the endoergicity of this reaction, but the available energy is again roughly evenly partitioned between the translation of 18O16O + 15N and the internal excitation of the molecular (O2) product. The relative yields of the three scattering pathways were determined to be 0.751 for inelastic scattering, 0.220 for O-atom exchange, and 0.029 for O-atom abstraction.