Formation of Iodine Monoxide Radical from the Reaction of CH2I with O2

The rate constants of IO radical formation from the reaction of CH 2 I with O 2 were determined in the pressure range of 5−80 Torr with N 2 diluent at 278−313 K, using cavity ring-down spectroscopy. The room temperature rate constant is (4.0 ± 0.4) × 10 -13 cm 3 molecule -1 s -1 at 30 Torr total pressure. No significant dependences on temperature and total pressure were observed. The yield of IO from CH 2 I + O 2 was estimated to be unity in 100 Torr total pressure of N 2 diluent.