Photoionization in Collision Complexes
Abstract
The overall objective of this effort was to determine the potential roles of van der Waals complexes of dioxygen, hydrocarbon fuel, and halon molecules in combustion and extinguishment. This study provides insights into the reactions between the fire extinguishant CF3Br and the dominant flame free radicals H, O, and OH. Molecular complexes of halon/dioxygen, halon/hydrocarbon, and hydrocarbon/dioxygen were generated by expansion of gas mixtures through a supersonic nozzle. These complexes then underwent dissociative photoionization followed by mass spectrometric analysis. Photoion yield curves were analyzed to characterize fragmentation processes and energy states. Thermodynamic properties of the clusters and fragments were measured. No evidence of interaction Of CF3Br with H atoms was found. Studies of frozen collision complexes offer a powerful method for elucidating the initial steps of reaction chemistry. Small heteroclusters were prepared, relative number densities of neutrals were determined, kinetic energy distributions of fragment ions were measured, and the first reported analysis of clusters in a ternary molecular beam was carried out. The results of these experiments have many potentially significant implications for development of alternative fire suppression agents.... Complexes, Clusters, Halon, Fuel, Oxygen, Radical, Mechanism, Extinguishment.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1991
- Accession Number
- ADA261124
Entities
People
- D. L. Arneberg
- E. A. Walters
- J. S. Nimitz
- J. T. Clay Jr.
- M. H. Wall