Relativistic configuration interaction calculations of multi-pole transitions rates and spectra of Ar I and Ar II

The relativistic configuration interaction method of the flexible atomic code (FAC) was used to calculate atomic data for multi-pole transitions in Ar I and Ar II. Large-scale calculations were performed to produce atomic structure and spectra data with Δn≠0 (n=3→4, 5, 6). Energy levels, oscillator strengths and transition rates are calculated for electric-dipole (E1), electric quadruple (E2), electric octupole (E3), magnetic dipole (M1), magnetic quadruple (M2) and magnetic octupole (M3) transitions. The produced atomic data are important in modeling of M-shell spectra of Ar ions in laser, astrophysics and plasma diagnostics. Correlation effects to all orders are considered in the calculations by the configuration interaction expansion, and all relativistic effects are included. Some calculated energy levels are compared against published values. An excellent overall agreement is observed.