A theoretical study of the np k configurations

Abstract

An up-to-date picture of the known np 2 and np 3 configurations is presented by plotting the reduced energy ϵ against ψ = ξ p /(5 F 2 + ξ p ) according to Edlén. It is concluded that the p 2 level values of S XI, Sc XVI, Ti XVII, V XVIII, Ni XV and Te III, and the p 3 level values of Al VII, Si VIII, P IX, Cl X, Se II and Xe IV need to be improved. Edlén's (1972) work on n = 2 and Svensson's (1971) work on n = 3 give a very satisfactory fit to our ψ-ϵ graphs. The ( F 2 - ξ p ) V s ψ graphs enable us to study coupling variations along the same and different isoelectronic sequences. The Z-dependence of the ground intervals 4 s 2 4 p 4 have been studied theoretically for the first time. The level values are represented, within less than 0.2% error, by semi-empirical formulae having 3–5 adjusted parameters and are based on data obtained from laboratory observations. The results provide means for checking laboratory and astrophycial identifications and measurements.