Oscillator strengths and transition probabilities for allowed and forbidden transitions in Fe XIX

Abstract

An extensive set of oscillator strengths, line strengths, and radiative decay rates for the allowed and forbidden transitions in Fe XIX is presented. They correspond to 1626 fine structure levels of total angular momenta 0 ≤ J ≤ 8 of even and odd parities with 2 ≤ n ≤ 10 , 0 ≤ l ≤ 9 , 0 ≤ L ≤ 10 , and ( 2 S + 1 ) = 1 , 3, 5. In contrast, the compiled table of the National Institute for Standards and Technology (NIST) lists only 63 observed levels. A total of 289,291 electric dipole allowed transitions are presented. They were obtained in the close coupling approximation using the relativistic Breit–Pauli R -matrix method. The wavefunction expansion included 15 levels of the configurations 2s 22p 3, 2s2p 4, and 2p 5 of the Fe XX core. The calculated fine structure levels are assigned with spectroscopic identifications using quantum defect analysis. Comparison with the observed energies shows very good agreement, the largest difference being less than 4%. The transitions also compare well with the compiled data by NIST and recent calculations. The forbidden transitions of the electric quadrupole and octupole, and magnetic dipole and quadrupole, type are presented for the 379 levels of the configurations 2s 22p 4, 2s2p 5, 2p 6, 2s 22p 33s, 2s 22p 33p, 2s 22p 33d, 2s 22p 34s, 2s 22p 34p, 2s 22p 34d, 2s 22p 34f, 2s2p 43s, 2s2p 43p, 2s2p 43d, 2s2p 44s, 2s2p 44p, and 2s 22p 23s 2 of Fe XIX. They correspond to a total of 66,619 transitions. These results have been obtained from relativistic Breit–Pauli atomic structure calculations using the program SUPERSTRUCTURE. The forbidden transition probabilities show very good agreement with those compiled by NIST.