Flash spectroscopy of multiphoton excited trifluoroiodomethane

1982 ◽  
Vol 86 (5) ◽  
pp. 731-736 ◽  
Author(s):  
W. Fuss
Keyword(s):  

The explosive oxidation of acetylene, initiated homogeneously by the flash photolysis of a small quantity of nitrogen dioxide, has been investigated by flash spectroscopy. The absorption spectra of OH, CH, C 2 (singlet and triplet), C 3 , CN and NH, a number of which have not previously been observed, are described, and the relative concentrations, at all times throughout the explosion, are given. Four stages have been distinguished in the explosive reaction: 1. An initial period during which only OH appears. 2. A rapid chain branching involving all the diatomic radicals. 3. Further reaction, occurring only when oxygen is present in excess of equimolecular proportions, during which the OH concentration rises exponentially and the other radicals are totally consumed. 4. A relatively slow exponential decay of the excess radical concentration remaining after completion of stages 2 and 3. The duration of stage 1 is 0 to 3 ms. In an equimolecular mixture at 20 mm total pressure, containing 1.5 mm NO 2 , the durations of both stage 2 and stage 3 are approximately 10 -4 s and the half-life of OH in stage 4 is 0.28 ms. A preliminary interpretation of these changes and of the radical reactions is given.


Transient absorption spectra have been obtained by pulsed radiolysis and flash spectroscopy of neutral and alkaline solutions of benzophenone under anaerobic conditions. These spectra demonstrate the formation of the ketyl radical ion (C 6 H 5 ) 2 Ċ—O - as a primary product resulting from electron attachment to benzophenone. In neutral solution, the rapid neutralization of the ketyl ion produces the neutral radical (C 6 H 5 ) 2 Ċ—OH, and this is shown by a change in the optical absorption spectrum. Neither of the absorption spectra due to these species is observed in acid solutions. These observations show that in neutral and alkaline solution, the hydrated electron reacts directly with the solute, whereas in acid solution it is converted to the hydrogen atom before reacting with the solute.


1987 ◽  
Vol 45 (2) ◽  
pp. 167-175 ◽  
Author(s):  
John M. Kelly ◽  
Wilhelm J. M. Putten ◽  
David J. Mcconnell

1976 ◽  
Vol 98 (2) ◽  
pp. 621-623 ◽  
Author(s):  
David Creed ◽  
Paul H. Wine ◽  
Richard A. Caldwell ◽  
Lynn A. Melton

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