nenad_milovanović
@astronomical_observatory
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At the Astronomical Observatory, Belgrade I am working in three different fields. First is investigation of spectral line profiles from stellar atmospheres and laboratory plasma. Using atomic data, I am calculating Stark broadening parameters for specific spectral line, which is most important broadening parameter for early-type and chemically peculiar (CP) stars. Due to the uncompleted atomic energy levels for ions of heavier atoms, I use, as calculation method for Stark broadening parameters, Modified Semiempirical Method (MSE) developed by Dimitrijević and Konjević (JQSRT (1980) 24, 451) for spectral line widths, and Kršljanin and Dimitrijević (Astronomy & Astrophysics (1986) 165, 269) for spectral line shifts. For synthesis of specific spectral line, I am using SYNTH program code (Piskunov, N.E. (1992), in Stellar Magnetism, Nauka, St. Petersburg, 92.) with broadening parameters obtained from MSE and Kurucz stellar model as input. After that, I compare theoretically evaluated spectral line shape with experimental line shape gained from either laboratory experiment or observation of stellar spectra. Until now, I had calculated and analyzed spectral lines of Zirconium and Neodymium. Dr Milan S. Dimitrijević, Dr Luka Č. Popović and I published this work in international scientific journals. Currently I am working on calculation, analysis and synthesis of spectra of single ionized Thallium and its appearance in spectra of χ Lupi star. Dr Luka Č. Popović, Dr Milan S. Dimitrijević and I are currently investigating spectral lines of C, N and O neutral to three time ionized atoms. Besides Dr Milan S. Dimitrijević and Dr Luka Č. Popović I am closely cooperating with Dr Ištvan Vince from Department of Astrophysics at Faculty of Mathematics, University of Belgrade on Sun spectral lines and with colegues from Faculty of Physics, University of Belgrade, Center for Science and Technological Development, Laboratory for Applied Spectroscopy, Belgrade and Institute for Physics, Department for Spectroscopy, Belgrade. I had presented my papers at four international and four national conferences and seminars. My present interest includes developing of computer programs for calculation of atomic structures and spectra for highly ionized heavy elements using various couplings (e.g. jj, jk, mixed…). Second field of interest is theoretical calculations of atomic parameters needed for spectral line calculations. I am using Cowan FORTRAN program code (R.D. Cowan: The Theory of Atomic Structure and Spectra, University of California Press, 1981) and MCHF atomic structure package for atomic calculations of heavy elements. My third field of interest at the Astronomical Observatory, Belgrade is database management. I had installed BELDATA, Belgrade Astronomical Observatory Database, which is database containing Stark broadening parameters, catalogues observed at Observatory and abstracts of papers published in journals of Astronomical Observatory. Database is installed on Linux based server in SQL language. Currently, I am working on the Internet connection of the database. Database was presented in JENAM-2000, Moscow and International Astronomical Union 24th General Assembly, Manchester conferences. I visited Vienna Atomic Line Database (VALD) in Vienna, Austria to establish closer cooperation between BELDATA and VALD. |
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