CROSSED MOLECULAR BEAM STUDIES OF CHEMILUMINESCENT REACTIONS: F{sub 2} + I{sub 2}, Br{sub 2} and ICl

Journal Article · Thu May 01 00:00:00 EDT 1980 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.439990· OSTI ID:1070082

Kahler, C C; Lee, Y T

The chemiluminescent bimolecular halogen-halogen reactions, F{sub 2} + I{sub 2}, Br{sub 2} and ICl, have been studied by the crossed molecular beam technique. Undispersed chemiluminescence was measured as a function of collision energy and, for I{sub 2} + F{sub 2}, as a function of the two beam pressures. Although no spectra were obtained to positively identify the emitters as IF*, ClF* and BrF*, arguments are given to support this identification. The observed reaction thresholds of 4.2 and 5.9 kcal/mole for I{sub 2} + F{sub 2} and ICl + F{sub 2} , respectively, are the same as the threshold energies for production of the stable trihalogens I{sub 2}F and ClF. This coincidence of threshold energies, as well as similar high collision energy behavior, implies that the chemiluminescent reaction proceeds via a stable trihalogen intermediate. This mechanism can explain our results and the results of other workers without resorting to a symmetry forbidden four center reaction mechanism. A threshold of 11.3 kcal/mole was found for Br{sub 2} + F{sub 2} , no threshold for Br{sub 2}F has been previously reported. Laser enhancement of the I{sub 2} + F{sub 2} reaction was attempted, but no enhancement was seen.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Materials Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1070082
• Report Number(s): LBL-11005
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 10 Vol. 73; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY