In the last years, the use of high-resolution spectrographs installed on large-aperture telescopes greatly increased the capacity of abundance analysis in stellar atmospheres. In order to extract more information from high resolution stellar spectra, it is necessary to take into account nuclear effects, such as hyperfine structure and isotopic shifts. Therefore, new laboratory studies of hyperfine structure constants are needed to calculate accurate abundances. Laser spectroscopy is one of the important methods to obtain the hyperfine structure constants.
Laser spectroscopy provides important experimental atomic and molecular data needed for various scientific areas such as plasma physics, gaseous electronics, astronomy, astrophysics, biomedicine and environmental applications. The results from spectroscopic measurements form the basis for international atomic and molecular databases. These data include line identification, wavelengths, energy levels, oscillator strengths as well as hyperfine structure and isotope shift data. In this project, our main aims are to find new energy levels, to classify unclassified lines in the spectra and to determine unknown hyperfine structure constants of atomic Niobium. For these purposes we will apply laser optogalvanic spectroscopy (LOGS) and laser induced fluorescence spectroscopy (LIFS) methods in the near infrared wavelength range.
Another aim of this work is to make a parametric analysis of the multi configurational fine and hyperfine structure for the even parity configurations by using all experimentally known hyperfine structure constants. Effective one-electron parameters will be determined and theoretical predictions will be given for the magnetic dipole hyperfine structure constants A for the levels of even parity configurations.

• Prof. Dr. habil. Sophie Kröger (Projektleitung)

Istanbul University

• Gönül Başar, Istanbul University, Faculty of Science, Department of Physics

Istanbul University BAP (Sientific Research Projects)

http://home.htw-berlin.de/~kroeger/Forschungsschwerpunkte.html