Systematic Studies of N IV Transitions of Astrophysical Importance

Abstract

E1, M2, M1 and E2 rates of transitions between n = 2 levels of N IV have been calculated using the two independent codes CIV3 and MCHF. Convergence of each of the approaches has been studied and comparisons made as the complexity of the calculations increases to include valence, core-valence and core-core correlation. The agreement between the two methods is sufficiently good to allow us to set quite narrow uncertainty bars. For the1S-1P0resonance line, our recommended f-value is 0.609 with an estimated uncertainty of 0.002, while our recommended A-value for the1S0-3P01intercombination line is 580 s-1with an estimated uncertainty of 10 s-1.