Relativistic oscillator strengths for the np2-np(n+1)s transitions

Abstract
Oscillator strengths are presented together with excitation energies for the np2 -np(n+1)s transitions in Ge I, As II, Sn 1, Sb II, Pb I and Bi II spectra computed using the relativistic configuration interaction (CI) approach. A slight modification in the standard CI method is proposed and investigated. The effect of the CI on calculated oscillator strengths computed in the Babushkin and Coulomb gauges is discussed. The results obtained are compared with other theoretical calculations as well as with available experimental data.
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