O2(b(1)Σ(+)(g), υ = 0, 1) relative yields in O((1)D) + O2 energy transfer.

Abstract

Energy transfer from O((1)D) to O2 is the main source of O2(b(1)Σ(+)(g) in vibrational levels υ = 0 and 1 in the Earth's thermosphere. Knowledge of the relative yields for O2(b(1)Σ(+)(g) production in υ = 0 and 1 is essential for a reliable interpretation and modeling of the O2 atmospheric band emissions (b(1)Σ(+)(g) - X (3)Σ(-)(g) from these two vibrational levels. We report laboratory measurements of the relative yields at room temperature. In the experiments, O2(b(1)Σ(+)(g), υ = 0, 1) is generated by O((1)D) + O2 collisions following partial photodissociation of O2 at 157.6 nm. O2(b(1)Σ(+)(g), υ = 0, 1) emission detection is used to monitor the temporal evolution of the vibrational level populations. The measured fractional yield for υ = 1 is 0.8 ± 0.1, in contrast with the results of previous studies that indicated dominant O2(b(1)Σ(+)(g), υ = 0) production. A revision is warranted of the values used for these relative yields in atmospheric models.