Calculation of the dipole-allowed excitations of the 3p(4)4s4p and 3p(4)3d4p configurations in argon

The energy spectrum of the argon 3p(4)4s4p and 3p(4)3d4p configurations wit h a total J = 1 was calculated within the single-configuration relaxed-core Hartree-Fock; approximation. The spin-orbit interaction was included in th e calculation. The results indicate strong mixing of the P-1 terms which ar e the ones allowed to couple to the ground state via electric-dipole excita tion. Most experimental lines could br identified using this calculation. T he calculated spin-orbit splittings within groups of levels are in very goo d agreement with experiment. However, differences of the order of 1 eV betw een experiment and theory were found for the absolute positions of groups o f levels. [S1050-2947(99)03702-6].