O2(b1∑g+,v=0,1) relative yields in O(1D)+O2 energy transfer.

Energy transfer from O(₁D) to O₂ is the main source of O₂(b¹∑_g⁺) in vibrational levels v = 0 and 1 in the Earth's thermosphere. Knowledge of the relative yields for O₂(b¹∑_g⁺) production in v = 0 and 1 is essential for a reliable interpretation and modeling of the O₂ atmospheric band emissions (b¹∑_g⁺-X³∑_g^- ) from these two vibrational levels. We report laboratory measurements of the relative yields at room temperature. In the experiments, O₂(b¹∑_g⁺,v=0,1) is generated by O(¹D) + O₂ collisions following partial photodissociation of O₂ at 157.6 nm. O₂(b¹∑_g⁺,v=0,1) emission detection is used to monitor the temporal evolution of the vibrational level populations. The measured fractional yield for v = 1 is 0.8±0.1, in contrast with the results of previous studies that indicated dominant O₂(b¹∑_g⁺,v=0,1)production. A revision is warranted of the values used for these relative yields in atmospheric models. [ABSTRACT FROM AUTHOR]