Line-strength of the 1.27-μm atmospheric transition of oxygen

The line-strength structure of the molecular oxygen near-IR atmospheric transition a1Δg(v′=0)-X3Σg-(v″=0) is deduced from experiment. Deviations from the expected structure, in terms of theoretical expressions, are put in evidence. As previously shown for the A band [G. Di Stefano, Chem. Phys. 302 (2004) 243], new expressions leading to a satisfactory agreement with the experiment are suited to a defined full (b) case of Hund, as a subsequent one to well-known intermediate (a-b) case.