Lifetimes in Mg I and Mg II; Beam-Foil Measurements and Numerical Coulomb-Approximation Calculations

Lifetime measurements using the beam-foil technique have been made for 10 levels in Mg I and for 11 levels in Mg II. Lifetimes have been calculated for the same levels using the numerical Coulomb-approximation (NCA) method, and the results are compared with the experimental data. Whereas good agreement exists between theory and experiment for Mg II levels and for some of the low lying Mg I levels, there are large disagreements for some higher lying levels in Mg I. Results from NCA calculations on ionized elements in the Mg I sequence are compared with experimental data. In some but not every case the NCA results agree with experimental data, as for Mg I.