J Van Blerkom

Transition Probabilities in the Ar i Spectrum

Relative line strengths have been computed for the transition arrays of 3p54s–3p54p and 3p54s–3p55p in Ar i. Intermediate-coupling theory has been used, starting from LS coupling, and using the experimental energy levels as data for determining the parameters of the theory by least-squares adjustment of the calculated energies. The results have been placed on an absolute scale using the Coulomb approximation. The Lande g factors computed agree well with the observed values. The calculated transition probabilities are in fairly satisfactory agreement with various experimental determinations, and this agreement is better than that obtained using either LS- or jl-coupling calculations. The results for the 4s–4p array appear to be more accurate than those for the 4s–5p array.

Low-energy electron scatter by Mg I

The electron collisional cross sections for the three lowest states of Mg I are calculated using the close coupling approximation with a semi-empirical core potential. Configuration interaction is included in the Mg I wave functions. Several resonances occur, a few of which strongly affect the total cross sections. Three elastic cross sections (31S-31S, 33P-33P and 31P-31P), and three inelastic cross sections (31S-33P, 31S-31P and 33P-31P) are presented.