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THE INFRARED MULTIPHOTON LASER CHEMISTRY OF TRIFLUOROBROMOMETHANE, KETENE, AND 1-CHLORO-1-FLUOROETHYLENE
Abstract
The infrared multiphoton dissociation (MPD) of trifluorobromomethane (CF(,3)Br), ketene, and 1-chloro-1-fluoroethylene (CH(,2)CClF) has been investigated. CF(,3)Br was photolyzed using the R(12) to R(34) lines of the 00(DEGREES)1-02(DEGREES)0 CO(,2) laser transition (9.317-9.201 (mu)). The effects of pulse number, pressure, and exciting wavelength were investigated. Products were determined by end-product analysis and a reaction scheme is proposed to account for the observed products and their dependence on the experimental conditions. The isotopic selectivity of the multiphoton process in CF(,3)Br was also investigated. Comparisons are presented between the results on CF(,3)Br and those of other freons and SF(,6). Ketene was photolyzed at 9.260 (mu). Products were determined by end-product analysis and monitoring of visible luminescence. The pressure dependence of the dissociation was also studied. A collision-assisted dissociation, followed by rephotolysis of the transient products is proposed to account for the results. Comparisons between the IR multiphoton dissociation and ultraviolet dissociation are also presented. CH(,2)CClF was photolyzed at two different wavelengths, 10.632 (mu) (P(24) of the 00(DEGREES)1-10(DEGREES)0 CO(,2) laser transition) and 9.552 (mu) (P(20) of the 00(DEGREES)1-02(DEGREES)0 CO(,2) laser transition). Two dissociation pathways were observed: elimination of HF and elimination of HCl. The dissociation processes were followed in real time by monitoring the IR fluorescence of the above two species. The effects of laser energy, bath gas pressure, and exciting wavelength upon the dissociation processes were investigated. The results are explained in terms of competition between the reaction pathways, optical pumping rates, and the rate of intermolecular energy transfer. Numerical modelling of the multiphoton process using energy-grained master equations is also presented. The validity and application of this approach is discussed. Results of modelling the fluence and pressure results of the MPD of CH(,2)CClF are presented.
Subject Area
Chemistry
Recommended Citation
JALENAK, WAYNE ALAN, "THE INFRARED MULTIPHOTON LASER CHEMISTRY OF TRIFLUOROBROMOMETHANE, KETENE, AND 1-CHLORO-1-FLUOROETHYLENE" (1982). ETD collection for University of Nebraska-Lincoln. AAI8217532.
https://digitalcommons.unl.edu/dissertations/AAI8217532