Formation of XO Radicals and Concentration Measurements

Formation of XO Radicals and Concentration Measurements.— Two reactions, (31) and (43), suitable for forming OO radicals in flow systems are available. Both 

Mass spectrometric studies of FO radical reactions have so far been confined to measurements at 298 K of the rate of the bimolecular FO + FO reaction. 

The difficulty in making systematic rate determinations for other FO reactions stems from the presence of O atoms or NO, which seem to be formed along with F atoms from the microwave discharge, and which react rapidly with FO. 

FO radicals can be formed either by the reaction of F with HOF [reaction (24)] or more conventionally by the reaction of F with O3 [reaction (29)]. Mass spectrometry is the only method so far to have been used successfully for the detection (and detomination) of FO radicals. Possible reasons for the failure to observe FO by e.p.r. or u.v. absorption spectroscopy have been discussed. The sensitivity of detection of FO by mass spectrometry is high, the lower concentration limit being 1 x 10 cm. The spectral background at mje 35 (O from HO etc.) limits the lowest detectable FO concentration.  

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