Magnetic dipole transitions of Pb-like ions from the multiconfiguration relativistic random-phase approximation

The multiconfiguration relativistic random-phase approximation theory is applied to magnetic dipole transitions in atoms. Excitation energies and oscillator strengths from the ground level ${}_{}{}^3{}_{}{}^{}$ ${\mathit{P}}_0$ to the excited level ${}_{}{}^3{}_{}{}^{}$ ${\mathit{P}}_1$ of Pb-like ions are calculated as prototypal examples. The first ${}_{}{}^3{}_{}{}^{}$ ${\mathit{P}}_1$ level for the neutral Pb atom, which is missing in the relativistic random-phase approximation, appears naturally in this theory, which accounts for two-particle–two-hole correlations.