Doubly-excited state resonances of the helium-like nitrogen ion N5+ near then=3 threshold of N6+

Abstract

Abstract. Excitation energies, eigenvectors, partial and total widths of the singlets 1p(-) and triplets 3p(-~ autoionising levels of the helium-like nitrogen ion N 5 + converging to the n = 3 excitation threshold of residual ion are calculated using the diagonalisation approximation in the LS coupling scheme. The analysis and comparison of our calculations with other theoretical calculations are done, and some conclusions are drawn about the diagonalisation approximation for the description of the problem of multichannel resonant photoionisation in heliumlike systems.