Photodissociation of methyl iodide at 229. 4 nm: A determination of the fragment recoil anisotropy using energy-selective electron impact ionization and time-of-flight mass spectrometry

Journal Article · Thu Sep 01 00:00:00 EDT 1988 · J. Chem. Phys.; (United States)

OSTI ID:6854475

Penn, S M; Hayden, C C; Carlson Muyskens, K J; Crim, F F

Energy-selective electron impact ionization of laser-produced photofragments together with time-of-flight mass spectrometry is a general and sensitive means of studying primary photodissociation processes. Low-energy electrons ionize photofragments without the production of background fragment ions from dissociative ionization of the parent molecules, and the time-of-flight mass spectral peak shapes provide direct information on the photofragment recoil anisotropy. In the first application of this combination of techniques, we have studied the photodissociation of methyl iodide at 229.4 nm, the short-wavelength end of the A band, in order to assess the contribution of transitions to the /sup 1/Q/sub 1/ state to the absorption profile. The results presented here show that I(/sup 2/P/sub 1//sub ///sub 2/) is the primary iodine--atom product and that the transition is largely parallel (..beta.. = (1.6 +- 0.1) for I(/sup 2/P/sub 1//sub ///sub 2/)) at 229.4 nm. These data together with previous photofragmentation results suggest that excitation to the /sup 3/Q/sub 0/ state dominates the entire A band absorption profile.

• Research Organization: Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
• OSTI ID: 6854475
• Journal Information: J. Chem. Phys.; (United States), Vol. 89:5
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
IODINE
ELECTRON-ATOM COLLISIONS
METHYL IODIDE
PHOTOLYSIS
METHYL RADICALS
ELECTRON-MOLECULE COLLISIONS
ANGULAR DISTRIBUTION
ANISOTROPY
IONIZATION
MASS SPECTROSCOPY
RECOILS
ALKYL RADICALS
ATOM COLLISIONS
CHEMICAL REACTIONS
COLLISIONS
DECOMPOSITION
DISTRIBUTION
ELECTRON COLLISIONS
ELEMENTS
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENS
IODINATED ALIPHATIC HYDROCARBONS
MOLECULE COLLISIONS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADICALS
SPECTROSCOPY
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena