LS-forbidden strength of atomic transition arrays

Abstract

In a transition array (i.e. the totality of the lines linking the levels of two electronic configurations), some lines are forbidden in pure LS coupling, and very weak in its vicinity. The total strength of this set of lines is evaluated statistically in terms of the parameters defining the coupling. The numerical application is made to the Fe V - array. Such an evaluation of the LS-forbidden strength is important for the computations of absorption coefficients and opacities.