Trends in E2 and M1 transition rates between 3p /2 and 3p 1/2 levels in 3s ^2 3p^ k systems

The analysis of forbidden lines, such as E2 and M1, in the atomic spectra emitted by certain ions is important for the study of the plasma in astrophysical objects and fusion devices. Transition rates between 3p 3/2 and 3p 1/2 levels in 3s ^2 3p^ k ions that belong to the aluminium sequence have been calculated with the Relativistic Quantum Defect Orbital (RQDO) method. The present data are tested by comparison with other theoretical data available in the literature, and the regularity of the transition intensities along the isoelectronic sequence for both (E2 and M1) lines, as well as their competition, are also analysed.