: |
: |
|---|
JIANDE HAN, ANATOLY V. KOMISSAROV, SCOTT P. TINNEY AND MICHAEL C. HEAVEN, Department of Chemistry, Emory University, Atlanta, GA 30322.
The reactions of O atoms with iodine containing molecules and the kinetics of the IO radical are of relevance to the removal of tropospheric ozone. These reactions, along with energy transfer processes involving electronically excited states of O2, are also relevant to a new class of oxygen-iodine lasers that employ discharge excitation.
Pulsed photolysis of CF3I/N2O/N2 mixtures and direct laser excitation of O2 in the presence of I2 have been used to investigate the iodine oxygen kinetics. The primary findings of this study are that O2 (a1
) is generated by the reactions IO+O
I+O2(a) and I+I+O2
I2+O2(a). O2(b) and O2(a) are removed by I2 with rate constants of 5.8x10-11 and <5x10-16 cm^ 3 s-1, respectively. The branching fraction for the physical quenching channel O2(b)+I2
O2(a)+I2 was found to be 0.4. Re-measurement of the rate constant for O2(a)+O2(X)
2O_ 2(X) yields a value of 9.3x10-19 cm3 s-1. This result is somewhat lower than previous estimates.