Relativistic oscillator strengths and excitation energies for the ns21S0-nsnp3P1,1P1transitions. II. Cadmium isoelectronic sequence

Abstract

For pt.I see ibid., vol.18, no.8, p.1533 (1985). Relativistic excitation energies and oscillator strengths for both the resonance transition 5s^{2 1}S₀-5s5p ¹P₁ and the intercombination lines 5s^{2 1}S₀-5s5p ³P₁ in the cadmium isoelectronic sequence are computed in an approach which combines limited relativistic configuration mixing to represent intravalence correlation with a polarisation model to account for valence-core correlation. This approach is able to greatly reduce the discrepancies between the theoretical and experimental oscillator strengths for these transitions. A substantial part of the remaining discrepancy, particularly for ionised systems, can probably be attributed to uncertainties in the available experimental data. Systematic trends along the sequence in both the oscillator strengths and in the relative contributions of intravalence and valence-core electron correlation are discussed and compared with those obtained previously for the mercury sequence. It is found that for spin-allowed transitions the share of intravalence correlation increases for lighter (lower Z) homologous systems in corresponding ionisation stages, whereas that of core-valence correlation decreases. For the spin-forbidden transitions, however, both correlation contributions seem to increase for lower Z homologues in the same ionisation stages.