Collision-induced absorption between O2–CO2 for the a1Δg (v = 1) ← X3Σ −g (v = 0) transition of molecular oxygen at 1060 nm

Abstract

Collision-induced absorption between O₂ and CO₂ molecules associated with the a¹Δ_g (v = 1) ← X³Σ⁻_g (v = 0) band of oxygen around 1060 nm was measured using cavity ring-down spectroscopy. The lineshape for this transition is measured for the first time, and the integrated cross-section is found to be smaller than the only previous report. For pure oxygen, we find an integrated absorption value of (2.10 ± 0.31) × 10⁻⁴ cm⁻² amg⁻² which is in good agreement with the previous reported values. For O₂–CO₂ collisions we report an integrated value of (6.37 ± 1.09) × 10⁻⁵ cm⁻² amg⁻² which is small but still significant and not accounted for by theory.