Pulse radiolysis of alkyl iodides and oxygen in the gas phase

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1981

OSTI ID:6010734

Ramirez, J E

Using a pulse radiolysis facility for the study of fast chemical kinetics in the gas phase established at the University of Florida Radiation Chemistry Laboratories, parameters relevant to a linear electron beam initiated atomic iodine laser, which would lase on the transition 5/sup 2/P/sub 1/2/ (I*) ..-->.. 5/sup 2/P/sub 3/2/ (I), have been investigated. Kinetic data for the parent compound quenching of I* were obtained by variation of the parent compound pressure at constant buffer gas pressure and observing I* decay rates versus time. Deactivation rate constants for the perfluoroalkyl iodides were found to be much lower than for alkyl iodides (in cm/sup 3//molec s): CH/sub 3/I, 2.0 +- 0.1 x 10/sup -13/; C/sub 2/H/sub 5/I, 5.0 +- 0.3 x 10/sup -13/; CF/sub 3/I, 8.8 +- 1.5 x 10/sup -16/; C/sub 2/F/sub 5/I, 9.7 +- 1.0 x 10/sup -15/; i-C/sub 3/F/sub 7/I, 1.7 +- 0.1 x 10/sup -15/; C/sub 4/F/sub 9/I, 1.8 +- 0.1 x 10/sup -14/. The extent of population inversion was investigated by measuring initial excited state and ground state atomic iodine concentrations and calculating the branching ratio, (I*)/sub 0//(I*)/sub 0//(I)/sub 0/: CH/sub 3/I, 2.7; CF/sub 3/I, 3.8; C/sub 2/F/sub 5/I, 2.7; i-C/sub 3/F/sub 7/I, 3.2; C/sub 4/FgI, 1.8. Perflouromethyl iodide showed the largest population inversion from electron beam irradiation. Using formation of O/sub 3/ from O/sub 2/ as the dosimeter (G = 13.8 molecules/100 eV for ozone), energy deposited per electron pulse in 750 torr O/sub 2/ was 7.3 x 10/sup 1/a* eV/g. Spectrophotometric detection of ozone utilized the 253.7 nm Hg line. The rate of formation of ground vibrational state ozone in the pulse radiolysis of oxygen was followed using the 253.7 nm Hg line. The rate of formation was found to be early second-order with a rate constant of 4.1 +- 0.4 x 10/sup -15/ cm/sup 3//molec s. It is formed from direct combination of oxygen atoms and oxygen molecules and from collisional quenching of vibrationally excited ozone and/or an electronically excited ozone precursor, probably ozone (/sup 3/B/sub 2/).

• Research Organization: Florida Univ., Gainesville (USA)
• OSTI ID: 6010734
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
IODINATED ALIPHATIC HYDROCARBONS
RADIOLYSIS
OXYGEN
ALKANES
ELECTRON BEAMS
PULSED IRRADIATION
REACTION KINETICS
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELEMENTS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
IRRADIATION
KINETICS
LEPTON BEAMS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PARTICLE BEAMS
RADIATION CHEMISTRY
RADIATION EFFECTS
400600* - Radiation Chemistry