Deexcitation of multiply-ionized atoms

Theoretical lifetimes, transition energies, and fluorescence yields are presented for the various spectroscopic terms of multiply-ionized silicon and fluorine. Numerical results are also reported for the 1s 2s nl and 1s 2p nl levels of argon for 2s less than or equal to nl less than or equal to 4f. A model is developed to provide a detailed description of the cascade feeding of the 1s 2s2, 1s2s2p, and 1s2p2 levels of argon. The range of atomic numbers is determined for which the radiative branch, 2p → 2s, is important in the deexcitation of the metastable states of the 1s2p/sup n/ configurations. The theoretical lifetimes are compared with the available experimental measurements for the 1s 2p24P J = 5/2, 3/2, 1/2 levels. The above numerical calculations are performed using the Hartree-Fock-Slater atomic model. The relativistic multi-configuration Hartree-Fock atomic model is used to determine the contribution of the magnetic dipole transition in the 1s2 2s 2p J = 2 levels of the Be isoelectronic sequence for a wide range of atomic numbers between Z = 9 and Z = 92. The relativistic effects on the nonradiative transition amplitude for the metastable 1s 2s 2pJ = 3/2, 1/2 levels are calculated with the relativistic Hartree-Fock-Slater atomic model for selected atomic numbers. The relativistic Hartree-Fock-Slater atomic model is also used to compare the relativistic effects with the role of the nonrelativistic configuration interaction in the deexcitation of the 1s 2s 3p 4P J = 5/2 level of argon