Contributions of Feshbach resonances to Stark broadening using the Gailitis formula: Quantum and semi-classical calculations for Ge  <scp>vi</scp> ion

Abstract We calculate in the present paper quantum and semi-classical perturbation Stark widths for the ion Ge vi, and we investigate the contributions of Feshbach resonances with the Gailitis approximation to the Stark broadening of spectral lines. We consider here 15 spectral lines. To the best of our knowledge, no theoretical or experimental Stark widths are available for the considered lines. The ion Ge vi is belonging to the set of trans-iron elements that have been recently identified in the ultraviolet spectrum of a DAO-type white dwarf BD-22°3467. Theoretical evaluations and measurements of atomic and Stark broadening data are a prerequisite for stellar-atmosphere modelling, which is a tool for the determination of the photospheric abundance of these species. Since there are no Stark broadening data for these ions, our calculations come to fill this gap, and the obtained results can be used for the abundance determination of elements, the calculation of stellar opacity, the interpretation and modelling of stellar spectra, the estimation of the radiative transfer through stellar plasmas, etc. They will be also implemented into the database of Stark broadening parameters STARK-B.