Fig. 2.
Typical transient absorption spectra recorded in the (CH3)2CI2/O2 photolysis system at selected delay times after the photolysis laser pulse (t = 0). Total pressure was 100.1 torr (PN2 = 89.9 torr, PO2 = 10.2 torr, [(CH3)2CI2]0 = 1.1 × 1014 cm−3). (A) Spectra recorded without adding SO2. (B) Spectra recorded at [SO2] = 5.3 × 1014 cm−3; (CH3)2COO was consumed by its reaction with SO2. (C) Difference spectra between the two sets of spectra in A and B. The main spectral carrier is assigned to (CH3)2COO because the reaction of (CH3)2COO with SO2 is fast. The residue contributions of the IO byproduct and the (CH3)2CI2 precursor are minor and have been removed in C.