A Empirical Determination of the Electric Dipole Moment Function and Transition Probabilities of Hydroxyl
Although intensity distributions derived from hydroxyl, OH(X^2pi), airglow observations are routinely used to determine rotational temperatures and vibrational level populations, the transition probabilities required to do so are in fact inadequately known. The set now in common use has come under attack both on theoretical grounds (because of the choice of theoretical dipole moment used in its derivation) and on experimental grounds (because of its failure to represent accurately measured intensity ratios). An electric dipole moment function (EDMF) for OH has been derived by combining recent high precision measurements of the permanent dipole moments with laboratory and airglow intensity measurements, including new night airglow measurements made specifically for this work. This empirical EDMF, while showing remarkable agreement with some a priori EDMF's, differs sufficiently to produce transition probabilities which are in much better agreement with airglow observations than previously available sets.
- Pub Date:
- Physics: Atmospheric Science