Transition probabilities in the A 2Σ+−X 2Πi electronic system of OH

A complete set of experimental vibrational band transition probabilities, including recent measurements on v′=2 and 3, allows us to calculate an empirical electronic transition moment, Re(r), for the A 2Σ+−X 2Πi system of OH, over the range of internuclear distance 0.70–1.70 Å. A comparison with an ab initio moment confirms that theoretical shape and validates its quantitative results, as the calculated Re(r) is within experimental uncertainty of the present result. The experimentally derived Re(r) is used along with Rydberg–Klein–Rees (RKR) wave functions to calculate transition probabilities for a wide range of vibrational and rotational levels. The study is extended to the isotope OD.