Resonances in Collision Strengths for Excitation of [O II] and [O III]

The collision strength for the transition |O⁺ 2s²2p³ \,²D3/2-²D5/2| has a complicated resonance structure at energies below the threshold for excitation of |O⁺ 2s²2p³ \,²P.| The collision strengths for the transitions |O²⁺ 2s²2p² \,³P⁻¹D, \,³P⁻¹S \,and ¹D⁻¹ S| contain near-threshold resonances due to collisional coupling between the configurations |2s²2p² \,and \,2s2p³.| The results obtained in recent calculations are presented in a form convenient for astrophysical applications. The resonances do not produce any large changes in the intensity ratios, [O II ] (λ 3729)/(λ 3726) and [O III ] (λ 4959 + λ 5007)/(λ 4363), as functions of electron temperature and electron density.