Measurements and empirical modeling of pure CO₂ absorption in the 2.3-μm region at room temperature: Far wings, allowed and collision-induced bands

Measurements of pure CO₂ absorption in the 2.3-μm region are presented. The 3800–4700-cm_-1 range has been investigated at room temperature for pressures in the 10–50-atm range by using long optical paths. Phenomena that contribute to absorption are listed and analyzed, including the contribution of far line wings as well as those of the central region of both allowed and collision-induced absorption bands. The presence of simultaneous transitions is also discussed. Simple and practical approaches are proposed for the modeling of absorption, which include a line-shape correction factor χ that extends to approximately 600 cm_-1 from line centers.