Transition probabilities in O III

Transition data has been computed in the MCHF + Breit-Pauli approximation for a number of the low lying triplets in O III. Special attention was given to the 2 p 3 p 3 P -2 p 3 d 3 P transition which is a primary cascade for the Bowen fluorescence mechanism in O III. The relativistic, largely spin-orbit, effect on the intensity ratio of primary decays was found to be as large as 50%, whereas the effect on secondary cascades was less than 30%. Agreement with astrophysically observed intensity ratios is excellent. There also is good agreement between the present liftimes and the beam-foil mean lifetimes obtained by Pinnington et al. , though for 2 p 3 p 3 D and 3 S the theoretical lifetimes are considerably shorter.