Collisional Removal of O2(b1Σg+,Ï =1) by O(3P)

The rate coefficient for collisional removal of O2(b1Σg+,υ=1) by O(3P), kO, is an essential parameter in modeling the emissions from O2(b1Σg+,υ=1) in the Earth's thermosphere. We report a laboratory measurement of this rate coefficient at room temperature. A fluorine laser is used to photodissociate O2 at 157.6 nm, followed by detection of the time-resolved fluorescence from subsequently generated O2(b1Σg+,υ=1). The determined value is kO=4.5-1.3+0.8×10-12cm3s-1(2σ). The rate coefficient for collisional removal of O2(b1Σg+,υ=1) by O2 is also determined, with a value of (1.5 ± 0.1) × 10−11 cm3 s−1.