A spectrokinetic study of CH2I and CH2IO2 radicals

✍ Scribed by Jens Sehested; Thomas Ellermann; Ole John Nielsen

• Book ID: 102928032
• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 775 KB
• Volume: 26
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550260204

✦ Synopsis

The UV absorption spectrum and kinetics of CHzI and CHzIOz radicals have been studied in the gasphase at 295 K using a pulse radiolysis W absorption spectroscopic technique. UV absorption spectra of CH2I and CHzIO2 radicals were quantified in the range 220-400 nm. The spectrum of CH2I has absorption maxima at 280 nm and 337.5 nm. The absorption cross-section for the CHzI radicals at 337.5 nm was (4.1 -C 0.9) x cm2 molecule-'. The UV spectrum of CHzIOz radicals is broad. The absorption cross-section at 370 nm was (2.1 5 0.5) X cm2 molecule-l. The rate constant for the self reaction of CH2I radicals, k = 4 X cm3 molecule-' s-' a t 1000 mbar total pressure of SFs, was derived by kinetic modelling of experimental absorbance transients. The observed self-reaction rate constant for CH2102 radicals was estimated also by modelling to k = 9 X 10-l' cm3 molecule-' s-'. As part of this work a rate constant of (2.0 % 0.3) X 10-lo cm3 molecule-' s-' was measured for the reaction of F atoms with CH3I. The branching ratios of this reaction for abstraction of an I atom and a H atom were determined to (64 -t 6)% and (36 2 6)%, respectively.