L. Natarajan

Kβ x-ray satellites of highly ionized iron

Relativistic configuration interaction calculations for the states of 1s3p q and 1s2s 2 3p q (q = 1-6) configurations of iron are carried out using multi-configuration Dirac-Fock wavefunctions in the active space interaction approach. The contributions from Breit interaction, quantum electrodynamics and nuclear mass corrections to the various initial and final levels are analysed to study the variations of these terms with the generalized occupation number of iron ionized to different degrees in the 3p shell. The sensitivity of the transition energies and rates to the small difference in the expansion model are also analysed by performing two sets of computations on the 1s2s 2 3p q multiplet states with and without the inclusion of the 2s core in the expansion set. The calculated values are compared with the other available data on He-like and Be-like iron and are found to be in very good agreement with them.

Spin-forbidden electric dipole transitions of highly ionized argon

Multiconfiguration Dirac-Fock and relativistic configuration interaction calculations with the inclusion of Breit interaction, quantum electrodynamics and finite nuclear mass corrections have been carried out in the extended optimal level scheme on the spin-forbidden electric dipole transitions of highly ionized argon. The calculations have been carried out in jj coupling with a single electron in the K shell, varying degrees of ionization in the L shell and open outer shells. The radiative transition rates have been calculated in Coulomb and length gauges. The sensitivity of the orbital wavefunctions and the effect of configuration interaction on the transition rates are analysed in some detail.

Multi-configuration Dirac-Fock and configuration-interaction calculations of Ar7+ to Ar17+ ions

Multi-configuration Dirac-Fock and relativistic configuration-interaction calculations with the inclusion of the Breit interaction, quantum electrodynamics and finite nuclear mass corrections have been carried out in the extended optimal level (EOL) scheme on the energy levels, electric dipole transition rates, oscillator strengths and radiative lifetimes of Ar17+ to Ar10+ ions. The calculations have been performed in JJ coupling with an empty K shell, open outer shells and varying degrees of ionization in the L shell. The effects of a transverse Breit interaction, finite nuclear mass corrections and quantum electrodynamics on the energy levels and radiative transition rates are analysed.

Two-electron one-photon transitions in atoms with 12 Z 80

Relativistic configuration interaction results are presented for the Kαα x-rays arising from the decay of doubly ionized K shell of atoms with 12 ≤ Z ≤ 80. The x-ray energies and dipole rates are calculated in the active space approximation using multi-configuration Dirac–Fock wavefunctions with the inclusion of the Breit interaction and quantum electrodynamics corrections. The calculations include all single and double excitations from core-valence interactions. The resulting length and velocity gauge transition rates are well converged and are in good agreement with the allowed transition, while the intercombination line rate is seen to be gauge dependent. Conclusions concerning the relative importance of correlation and the Breit interaction on the intensity ratios are obtained in some detail. The sensitivity of the relative intensities of the fine structure lines to the coupling variations in both length and velocity gauges is analysed. The calculated results are compared with previous experimental and theoretical data.