Large - scale Breit - Pauli R - matrix calculations for transition probabilities of Fe V Sultana N . Nahar and Anil

Ab initio theoretical calculations are reported for the electric (E1) dipole allowed and intercombination fine structure transitions in Fe V using the Breit-Pauli R-matrix (BPRM) method. We obtain 3865 bound fine structure levels of Fe V and 1.46 × 10 oscillator strengths, Einstein A-coefficients and line strengths. In addition to the relativistic effects, the intermediate coupling calculations include extensive electron correlation effects that represent the complex configuration interaction (CI). For bound-bound transitions the BPRM method, based on atomic collision theory, entails the computation of the CI wavefunctions of the atomic system as an (electron + target ion) complex. The target ion Fe VI is represented by an eigenfunction expansion of 19 fine structure levels dominated by the spectroscopic configuration 3d, and a number of correlation configurations. Fe V bound levels are obtained with angular and spin symmetries SLπ and Jπ of the (e + Fe VI) system such that 2S+1 = 5,3,1, L ≤ 10, J ≤ 8. The bound levels are obtained as solutions of the Breit-Pauli (e + ion) Hamiltonian for each Jπ, and are designated according to the ‘collision’ channel quantum numbers. A major task has been the identification of these large number of bound fine structure levels in terms of standard spectroscopic designations. A new scheme, based on the analysis of quantum defects and channel wavefunctions, has been developed. The identification scheme aims particularly to determine the completeness