1. Measurement of the rate coefficient for collisional removal of O2(X 3Σg-,υ=1) by O(3P).
- Author
-
Kalogerakis, Konstantinos S., Copeland, Richard A., and Slanger, Tom G.
- Subjects
- *
COLLISIONS (Nuclear physics) , *ENERGY transfer , *PHOTOCHEMISTRY , *PHYSICAL & theoretical chemistry , *PHOTOSYNTHETIC oxygen evolution , *OZONE , *FORCE & energy - Abstract
We report a laboratory measurement of the rate coefficient for the collisional removal of O2(X3Σg-,υ=1) by O(3P) atoms. In the experiments, 266-nm laser light photodissociates ozone in a mixture of molecular oxygen and ozone. The photolysis step produces vibrationally excited O2(a1Δg) that is rapidly converted to O2(X3Σg-,υ=1–3) in a near-resonant electronic energy-transfer process with ground-state O2. In parallel, a large amount of O(1D) atoms is generated that promptly relaxes to O(3P). Under the conditions of the experiments, only collisions with the photolytically produced O(3P) atoms control the lifetime of O2(X3Σg-,υ=1), because its removal by molecular oxygen at room temperature is extremely slow. Tunable 193-nm laser light monitors the temporal evolution of the O2(X3Σg-,υ=1) population by detection of laser-induced fluorescence near 360 nm. The removal rate coefficient for O2(X3Σg-,υ=1) by O(3P) atoms is (3.2±1.0)×10-12 cm3 s-1 (2σ) at a temperature of 315±15 K (2σ). This result is essential for the analysis and correct interpretation of the 6.3-μm H2O(ν2) band emission in the Earth’s mesosphere and indicates that the deactivation of O2(X 3Σg-,υ=1) by O(3P) atoms is significantly faster than the nominal values recently used in atmospheric models. [ABSTRACT FROM AUTHOR] more...
- Published
- 2005
- Full Text
- View/download PDF