The 1909 Å intercombination line in C III

Abstract

The configuration interaction code CIV3 is used to calculate the A-value for the 1909 Å 2s2 1S0-2s2p3Po1 intercombination line in C III. An extensive calculation of valence shell correlation is augmented by the inclusion of core polarization effects both explicitly through further configurations with one or both 1s orbitals replaced by correlation orbitals, and also by the use of model potentials. Our recommended value of 104 ± 4s−1 for the A-value lies somewhat lower than the experimentally determined value of 121 ± 7s−1. We have estimated the expected error in our work by considering the extent of the convergence of our calculation. We also calculated the resonance transition and obtain an oscillator strength in excellent agreement with experiment.