Milan S. Dimitrijevic

Ab Initio Determination of Atomic Structure and Stark Broadening Parameters: Pb IV and Recent Results

Abstract We present a review of our previous ab initio calculations of Stark broadening parameters using semi-classical perturbation method for the calculation of Stark widths and shifts, and the SUPERSTRUCURE (SST) code for the determination of atomic structure. SST code takes into account the configuration interactions and relativistic effects. New results are also presented for some spectral lines of Pb IV. Energy levels and oscillator strengths are calculated using Hartree-Fock relativistic approach, and the Stark broadening parameters are determined using a semiclassical perturbation approach.

24th Summer School and International Symposium on the Physics of Ionized Gases

This volume of the Journal of Physics: Conference Series contains the Invited lectures, Topical invited lectures and Progress reports presented at the 24th Summer School and International Symposium on the Physics of Ionized Gases – SPIG 2008. The conference was held in Novi Sad, Serbia, 25–29 August 2008. Throughout the history of scientific discovery, one can see repeatedly how fundamental sciences have solved basic questions and opened new frontiers. In the field of physics, there are many key discoveries, resulting in their useful applications for the benefit of the mankind. It is very important to have meetings to discuss actual problems in particular fields of physics. This Conference provided a forum for 160 active researchers from 25 countries to discuss current advances in the physics of ionized gases and related fields. The Conference has a long tradition. Let us remember that the first SPIG was organized in 1968. The decay of former Yugoslavia in 1991, caused a disturbance in SPIG meetings, but fortunately, in 1993, SPIG meetings were successfully revitalized. During recent years we have met successively in Belgrade, Kotor, Zlatibor, Soko Banja, Tara, Kopaonik and finally this time in Novi Sad. The structure of the papers in this Proceedings is as follows: Atomic Collision Processes, Particle and Laser Beam Interactions with Solids, Low Temperature Plasmas and General Plasmas. We hope that this Proceedings will be an important source of information, first of all to students, and also to plasma physics scientists. First of all, we would like to thank to the invited speakers for participating at the SPIG 2008 and for their efforts writing contributions for this Proceedings. We also express our gratitude to the members of the Scientific and Organizing committees for their efforts in organizing the Conference. Especially we would like to thank the Ministry of Science and Technological Development of the Republic of Serbia for financial support. Also, this Conference was a conference sponsored by the European Physical Society (EPS). And finally we are grateful to all participants for useful contributions and useful discussions. Gordana Malovic, Luka C Popovic and Milan S Dimitrijevic

Simple convergent formula for estimating stark widths of neutral atom lines

A simple analytical expression for estimating Stark widths of neutral atoms has been derived from a convergent theory that avoids the computation of the minimum impact parameter. The formula obtained was applied to He I lines. The results are compared to other calculations.

Mol-D a Database and a Web Service within the Serbian Virtual Observatory and the Virtual Atomic and Molecular Data Centre.

In this contribution we report the current stage of the MOLecular Dissociation (MOL-D) database which is a web service within the Serbian virtual observatory (SerVO) and node within Virtual Atomic and Molecular Data Center (VAMDC). MOL-D is an atomic and molecular (A&M) database devoted to the modelling of stellar atmospheres, laboratory plasmas, industrial plasmas etc. The initial stage of development was done at the end of 2014, when the service for data connected with hydrogen and helium molecular ions was done. In the next stage of the development of MOL-D, we include new cross-sections and rate coefficients for processes which involve species such as XH+, where X is atom of some metal. Data are important for the exploring of the interstellar medium as well as for the early Universe chemistry and for the modeling of stellar and solar atmospheres. In this poster, we present our ongoing work and plans for the future.

VAMDC FP7 project and STARK‐B database: C II Stark broadening parameters for white dwarf atmospheres research

Stark broadening parameters of C II lines were determined within 3d-nf series using semiclassical perturbation method. The atomic energy levels needed for calculations were taken from TOPBASE as well as the oscillator strengths, which were additionally calculated using the method of Bates and Damgaard. The both results were compared and only insignificant differences were found. Calculations were performed for plasma conditions relevant for atmospheres of DQ white dwarfs and for a new type of white dwarfs, with surface composed mostly of carbon, discovered in 2007 by Dufour et al. The aim of this work is to provide accurate C II Stark broadening data, which are crucial for this type of white dwarf atmosphere modellisation. Obtained results will be included in STARK-B database (http://stark-b.obspm.fr/), entering in the FP7 project of European Virtual Atomic and Molecular Data Center VAMDC aiming at building an interoperable eInfrastructure for the exchange of atomic and molecular data (http://www.vamdc.org/).

On the Stark broadening of Mg II spectral lines

Using a semiclassical approach, we have calculated electron-, proton-, and ionized helium-impact line widths and shifts for 67 Mg II multiplets. The obtained results have been compared with available experimental and theoretical data. The complete results will be published elsewhere. Here, we discuss the comparison of our results with experimental and other theoretical data.

On the Stark broadening of B III spectral lines

Using a semiclassical approach, we have calculated electron-, proton-, and ionized helium-impact line widths and shifts for 12 Be III and 27 B III multiplets. The obtained results have been compared with available experimental and theoretical data. The complete results will be published elsewhere. Here, we discuss the comparison of results for B III, with experimental and other theoretical data.

The flux ratio of the [OIII] λ λ 4959, 5007 Å lines in AGN

Up to now, all direct observational checks of the theoretical [OIII] 5006.843/4958.511 intensity ratio have been made for photoionized gaseous nebulae spectra. However, in some papers analyzing spectra of quasars, galaxies and AGN, this ratio is obtained as by‐product, used as a checking method or may be derived from published results. Recently, taking into account relativistic corrections to the magnetic dipole operator, Storey and Zeippen obtained the line intensity ratio of 2.98. In order to check that new value using the AGN spectra, we present the measurements of flux ratio of [OIII] λ λ 4959, 5007 A emission lines for a sample of 62 AGN, obtained from SDSS Database and from the published observations. We selected the sample using criteria of high signal to noise ratio and that line shapes of 4959 and 5007 are the same. We found that flux ratio is 2.993 ± 0.014, which is in a good agreement with the theoretical value of 2.98 given by Storey and Zeippen (2000).

Stark Broadened Line Profiles of Neutral Strontium Lines in Plasma Conditions

During more than twenty years, we are making a continuous effort to provide Stark-broadening parameters needed for research of astrophysical, laboratory and laser produced plasma. A review of our results is presented in Dimitrijevic, 1996). Such data are of interest for the consideration of a number of problems in astrophysics, physics and technology as e.g. for stellar plasma diagnostic, opacity calculations, the investigation/modelling of stellar spectra or a particular line, laboratory plasma diagnostic, laser produced plasmas, thermonuclear research, plasma technology, as well as for different examinations of regularities and systematic trends for e.g. homologous atoms (Dimitrijevic and Popovic, 1989) or in general (Puric et al. 1991).

Line Broadening Data: Stark Broadening of Ca II Sc III And Ti IV Lines

Electron– and proton–impact line widths and shifts for important Ca II, Sc III and Ti IV lines, have been calculated using the semiclassical–perturbation formalism. The obtained results were used to investigate the behaviour of Stark broadening parameters within the K I isoelectronic sequence.