Theoretical values for the [O iii] 5007/4959 line-intensity ratio and homologous cases |
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Authors: | P J Storey C J Zeippen |
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Institution: | University College London, Department of Physics and Astronomy, Gower Street, London WC1E 6BT; UMR 8631 (associée au CNRS et àl'UniversitéParis 7) et DAEC, Observatoire de Paris, F-92195 Meudon, France |
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Abstract: | The magnetic-dipole probabilities for the 1D2–3P2 and 1D2–3P1 transitions in carbon-like and oxygen-like ions are calculated up to atomic number Z =12, including relativistic corrections to the magnetic dipole operator. The ratio of the probabilities for these two transitions is found to change by up to 5 per cent compared with previous theoretical work, none of which included these relativistic corrections, with the effect being largest for the near neutral ions. The transition probability ratio for the O iii ] 5007 and 4959 Å lines is found to be 3.01, implying an intensity ratio of 2.98, in significantly better agreement with the observed ratio than the earlier theoretical work. |
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Keywords: | atomic data line: formation techniques: spectroscopic H ii regions planetary nebulae: general |
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