Accurate wavelengths, oscillator strengths and hyperfine structure in selected praseodymium lines of astrophysical interest

The spectra of singly and doubly ionized praseodymium have been observed by means of Fourier transform spectroscopy in the region 2800-8000 Angstrom. In Pr II improved wavelengths are reported for 49 lines. For 31 lines gf-va lues have been determined by means of branching fractions combined with rec ently measured lifetimes. The hyperfine structure patterns have been analyz ed for 44 lines, and magnetic hyperfine constants A have been derived for 8 odd and 18 even levels. Using the observed Pr II transitions improved ener gy levels are reported. Accurate wavelengths are given for 15 strong transi tions in Pr III. The gf-values from this study have been applied to obtain and discuss the solar abundance of praseodymium.