Dynamics of infrared multiphoton dissociation of SF/sub 6/ by molecular beam method. [Nonrandomize excitation energy]

Conference · Sat Jan 01 00:00:00 EST 1977

OSTI ID:7254441

Grant, E R; Coggiola, M J; Lee, Y T; Schulz, P A; Shen, Y R

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: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7254441
• Report Number(s): LBL-6035; CONF-770435-2
• Conference Information: 6. international symposium on molecular beams, Noordwijkerkout, Netherlands, 18 Apr 1977
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
BEAMS
CHEMICAL REACTIONS
COLLIDING BEAMS
DECOMPOSITION
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFRARED RADIATION
MOLECULAR BEAMS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATIONS
RECOILS
SULFUR COMPOUNDS
SULFUR FLUORIDES
VELOCITY
VIBRATIONAL STATES