Accession Number : ADA289447

Title :   Collisional Dynamics and Spectroscopic Studies of Highly Excited Rovibrational Levels of I(2)X(0(+) sub g) via Stimulated Emission Pumping.

Descriptive Note : Doctoral thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Nowlin, Melvin L.

PDF Url : ADA289447

Report Date : NOV 1994

Pagination or Media Count : 309

Abstract : Highly excited vibrational levels of iodine 2 (X) are thought to play an important role in the mechanism of iodine dissociation in the chemical oxygen iodine laser. It has been proposed that Iodine 2 is dissociated in the laser with processes such as Iodine 2(X;v"=0) + M*yields iodine 2, Iodine 2 (X;v">20) + M , Iodine 2(X;v">20) + M* yields Iodine 2(A sub 1v) + M , Iodine 2(X;v">20)+M* yields 2 Iodine +M where M* Iodine((2)Psub 1/2) or O2((1) delta), and M is O2((3) sigma) or iodine(2)Psub 3/2). In the chain branching mechanism, initiation would involve near-resonant E-V transfer populating vibrational levels around v"=40. Consequently, the relaxation dynamics of these levels are of interest as they may control the efficiency of the laser. I have examined the nascent state distribution of the iodine 2( X) product using pulsed laser photolysis and probe techniques. In these experiments, iodine((2)P1/2) was generated by 496 nm photolysis of iodine 2. Within several microseconds after the photolysis laser, iodine 2 (X;23<v'47) is detected by laser excitation of the D-X transition at wavelengths in the 280 - 300 nm range. Rotationally-resolved spectra under single collision conditions were recorded for the D-X transitions 4<v'<12 (left arrow) 23<v"<47. Analysis of the data indicated that the molecular constants for the D state did not extrapolate to the v'<3 0 levels reliably. In order to improve the characterization of the D state, a least-squares analysis generated improved spectroscopic constants.

Descriptors :   *EMISSION, *VIBRATION, *STIMULATION(GENERAL), *SPECTROSCOPY, *EXCITATION, *IODINE, *ROTATION, *COLLISIONS, *CHEMICAL LASERS, *PUMPING, PROBES, PHOTOLYSIS, DISTRIBUTION, DYNAMICS, MOLECULES, EFFICIENCY, PULSED LASERS, LASERS, OXYGEN, CONSTANTS, LEAST SQUARES METHOD, RELAXATION, DISSOCIATION.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE