Relativistic many-body calculations of electric-dipole lifetimes, transition rates, and oscillator strengths for n=3 states in Al-like ions

Abstract

Transition rates, oscillator strengths, and line strengths are calculated for electric-dipole (E1) transitions between even-parity 3 s3 p 2, 3 s 23 d, 3 p 23 d, 3 d 23 s, and 3 d 3 states and odd-parity 3 s 23 p, 3 p 3, 3 s3 p3 d, and 3 d 23 p states in Al-like ions with the nuclear charges ranging from Z=15 to 100. Relativistic many-body perturbation theory (MBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a 1 s 22 s 22 p 6 Dirac–Fock potential. First-order MBPT is used to obtain intermediate coupling coefficients and second-order MBPT is used to calculate transition matrix elements. Contributions from negative-energy states are included in the second-order E1 matrix elements to ensure gauge-independence of transition amplitudes. Transition energies used in the calculation of oscillator strengths and transition rates are from second-order MBPT. Transition rates, line strengths, and oscillator strengths are compared with critically evaluated experimental values and with results from other recent calculations. We present data for selected transitions between 10 of the possible 73 even-parity 3 s3 p 2, 3 s 23 d states and 29 of the possible 75 odd-parity 3 s 23 p, 3 p 3, and 3 s3 p3 d states in Al-like ions. Trends of the transition rates as functions of Z are illustrated graphically for 220 of the 3220 possible transitions. Lifetimes of the 10 even-parity lower levels and the 27 odd-parity upper levels are given for Z=15–100.