Allowed and forbidden transition parameters for Fe XV

Abstract

A comprehensive set of fine structure energy levels, oscillator strengths ( f), line strengths ( S), and radiative decay rates ( A) for bound–bound transitions in Fe XV is presented. The allowed electric dipole (E1) transitions were obtained from the relativistic Breit–Pauli R-matrix method which is based on the close coupling approximation. A total of 507 fine structure energy levels with n ⩽ 10, l ⩽ 9, and 0 ⩽ J ⩽ 10 are found. They agree within 1% with the available observed energies. These energy levels yield a total of 27,812 E1, same-spin multiplets and intercombination transitions. The A values are in good agreement with those compiled by NIST and other existing values for most transitions. Forbidden transitions are obtained from a set of 20 configurations with orbitals ranging from 1s to 5f using the relativistic code SUPERSTRUCTURE (SS) in the Breit–Pauli approximation. From a set of 123 fine structure levels, a total of 6962 S and A values are presented for forbidden electric quadrupole (E2), electric octupole (E3), magnetic dipole (M1), and magnetic quadrupole (M2) transitions. The energies from SS calculations agree with observed energies to within 1–3%. A values for E2, M1 transitions agree very well with the available values for most transitions while those for M2 transitions show variable agreement. The large set of transition parameters presented should be applicable for both diagnostics and spectral modeling in the X-ray, ultraviolet, and optical regions of astrophysical plasmas.