Relativistic many-body calculations of electric-dipole transitions betweenn=2states in B-like ions

Abstract

Transition rates, oscillator strengths, and line strengths are calculated for the 49 possible electric-dipole transitions between the eight even-parity 2s2p{sup 2} states and the seven odd-parity 2s{sup 2}2p and 2p{sup 3} states in boronlike ions with nuclear charges ranging from Z=6 to 100. Relativistic many-body perturbation theory (MBPT), including the Breit interaction, is used to evaluate retarded E{sub 1} matrix elements in length and velocity forms. The calculations start from a 1s{sup 2} 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 E{sub 1} matrix elements to ensure gauge independence of transition amplitudes. The 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. Lifetimes of the five possible odd-parity upper levels and the five possible even-parity upper levels are given for Z=6{endash}100. Trends of the transition rates as functions of {ital Z} are illustrated graphically for selected transitions. thinsp {copyright} {ital 1999} {ital The American Physical Society}