Theoretical relativistic oscillator strengths I. Transitions in principal, sharp, and diffuse series of Al I, Ga I, In I, and Tl I spectra

Abstract

The oscillator strengths for the sharp, principal, and diffuse series in the spectra of Al I, Ga I, In I, and Tl I are calculated as well as the lifetimes of their lowest excited states. The wave functions that were used were calculated by employing a relativistic semiempirical method which included exchange effects. Very good agreement with the most reliable experimental data was obtained for the f_ik values in the sharp series as well as for the calculated lifetimes. The discrepancies in the diffuse series are ascribed to the failure of the one-electron approach in the case of strongly perturbed series. The observed deviations in the relative line strengths from the values predicted neglecting the spin–orbit interaction were also investigated. Some systematic trends in the calculated oscillator strengths that were found for the sharp and principal series appear to be corroborated by experimental data for the sharp series in the spectra of Al I, Ga 1, In I.andTl 1.