Modelling of emission spectra of Pr I by summarizing hyperfine patterns of overlapping spectral lines

We present studies of the hyperfine (hf) structure of spectral lines of Praseodymium (Pr) by laser spectroscopic investigations as well as by analyzing Fourier Transform (FT) spectra. The experimental part of our work is done with the technique of laser-induced fluorescence (LIF) spectroscopy in a hollow cathode lamp. We present detailed studies of the very small region of 1.5 Angstroms (from 5810.5 to 5812.0 Angstroms) in the visible area of the FT spectrum where at least 14 spectral lines are overlapping. In the investigated region we discovered two new even levels and three new odd levels and could classify 11 new spectral lines. The final goal is to model the emission spectrum by a sum of the hf profiles of all spectral lines in a certain region. Application of such modelling may be found in analyzing highly resolved stellar spectra. (authors)