Optimization of coupling scheme in 2pN3l (N = 2, 3, 4 and l = s, p, d) isoelectronic sequences

Energy levels of highly charged ions as a rule cannot be classified using LS coupling. The study of the coupling schemes of ions with configurations 1s22s22pN3l (N = 2, 3, 4, l = 0, 1, 2) is presented. The suggestions on the choice of the sets of approximate quantum numbers for the identification of atomic state functions and the classification of atomic energy levels are formulated. The study is performed using a program Laris. The program is designed for the identification of atomic state functions and classification of atomic spectra by means of various sets of approximate quantum numbers and choosing in such a way the optimal one.