Dynamics of infrared multiphoton dissociation of SF/sub 6/ by molecular beam method. [Nonrandomize excitation energy]
The decomposition of polyatomic molecules by infrared multiphoton absorption is a subject which is under extensive investigation in many laboratories. The process has been shown to be efficient, selective and collisionless. The physical principles which are mainly responsible for the absorption of a large number of photons by an isolated molecule under intense infrared laser radiation have been elucidated through many experimental and theoretical investigations. However, one very important question which remains to be answered is the relation between the dynamics of molecular decomposition and the degree of vibrational excitation, i.e., the question of whether the excitation energy is completely randomized before molecular decomposition. The production of electronically excited fragments in the dissociation of halogenated hydrocarbons and the observations of SF/sub 4/ fragment in the decomposition of SF/sub 6/ without the evidence of the formation of lower energy SF/sub 5/ fragment provided some basis of speculation that the excitation energy might not be randomized before the dissociation of excited molecules. A crossed molecular beam apparatus has been adapted to study the dynamics of excitation and dissociation of polyatomic molecules in intense IR laser fields. Initial experiments have involved the study of the dissociation of SF/sub 6/ by CO/sub 2/ laser radiation at 10.6 ..mu..m. a molecular beam of SF/sub 6/ was formed by supersonic expansion using three stages of differential pumping. A grating tuned pulsed CO/sub 2/ TEA laser was used as the excitation source. The laser beam was focused by a 25 cm focal length ZnSe lens, and crossed the molecular beam near its focal point. The fragments produced by multiphoton dissociation of SF6 within the small interaction region were detected as a function of recoil angle and velocity.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7254441
- Report Number(s):
- LBL-6035; CONF-770435-2
- Resource Relation:
- Conference: 6. international symposium on molecular beams, Noordwijkerkout, Netherlands, 18 Apr 1977
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SULFUR FLUORIDES
PHOTOLYSIS
ANGULAR DISTRIBUTION
COLLIDING BEAMS
EXCITATION
INFRARED RADIATION
MOLECULAR BEAMS
RECOILS
VELOCITY
VIBRATIONAL STATES
BEAMS
CHEMICAL REACTIONS
DECOMPOSITION
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
SULFUR COMPOUNDS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena