Crossed molecular beam studies of chemiluminescent reactions: F/sub 2/+I/sub 2/, Br/sub 2/, and ICl

Journal Article · Sat Nov 15 00:00:00 EST 1980 · J. Chem. Phys.; (United States)

OSTI ID:6815474

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 ClIF. 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 attemped, but no enhancement was seen.

• Research Organization: Materials and Molecular Research Division, Lawrence Berkeley Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720
• OSTI ID: 6815474
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 73:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
BROMINE
CHEMICAL REACTIONS
CHEMILUMINESCENCE
CHLORIDES
CHLORINE COMPOUNDS
COLLIDING BEAMS
COLLISIONS
ELEMENTS
FLUORINE
HALIDES
HALOGEN COMPOUNDS
HALOGENS
IODINE
IODINE CHLORIDES
IODINE COMPOUNDS
LUMINESCENCE
MOLECULAR BEAMS
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NONMETALS