NONUNIFORM VARIATION OF THE RADIATIVE LIFETIMES OF BOUND EXCITED-STATES ALONG THE MG ISOELECTRONIC SEQUENCE

We present the result of a simple nonvariational configuration-interaction calculation for the energy levels and the radiative lifetimes of the Mg isoelectronic sequence. Emphasis is placed on the nonuniform variation of the radiative lifetimes for a series of singly excited states along the isoelectronic sequence due to the strong configuration mixing between the singly excited series and the doubly excited perturbers. The energy contributions from the bound-continuum type of configurations corresponding to the combination of negative- and positive-energy orbitals for the two valence electrons in a divalent atom are examined in detail within the frozen-core Hartree-Fock approximation. Comparisons with existing theoretical and experimental data are also presented.