AN EFFICIENT METHOD FOR COMPUTING RELATIVISTIC MIXING IN COMPLEX SPECTRA - APPLICATION TO SEXTET QUARTET MIXING IN CR-II

Structure and oscillator strength calculations are performed for the Cr II ion in intermediate coupling. Certain important correlation configurations contribute large numbers of levels which makes the problem very demanding in computing resources. A method of selecting a 'natural' basis for the algebraic expansion states is demonstrated. This method results in very substantial reduction in the size of the problem and allows one to investigate large relativistic mixing problems that might otherwise be intractible. The method is applied to the level structure arising from mixing the 4p 6D o, 6P o and 4P o terms in Cr II. Results are reported for oscillator strengths for transition from these levels to the levels arising from 3d 5 6S and 4s 6D terms. © 1990 IOP Publishing Ltd.