Semi-empirical analysis of the fine structure and oscillator strengths for atomic strontium

•The semi-empirical method of parameterization of the fine structure and the oscillator strengths.•Illustration of the method application for the example of Sr I data.•Predicted values of oscillator strengths for transitions from odd levels of Sr I in a wide spectral range.•Calculated values of the radiative lifetimes.

As the result of our studies on the atomic structure of complex atoms we produced high quality wave functions for both even and odd systems of configurations of Sr I. These wave functions were used for the parametrization of the oscillator strengths for electric-dipole transitions, where reliable data were available. The angular coefficients of the transition matrix in pure SL coupling were calculated by means of straightforward Racah algebra. The transition matrix was transformed into the actual intermediate coupling by the fine structure wave functions. The transition integrals were treated as free parameters in the least squares fit to the gf values. This procedure allowed us to obtain the values of the transition integrals and predict the values of oscillator strengths for the transitions from odd levels in a wide spectral range.